WorldWideScience

Sample records for beaufort sea

  1. Investigating Arctic Sea Ice Survivability in the Beaufort Sea

    Directory of Open Access Journals (Sweden)

    Matthew Tooth

    2018-02-01

    Full Text Available Arctic sea ice extent has continued to decline in recent years, and the fractional coverage of multi-year sea ice has decreased significantly during this period. The Beaufort Sea region has been the site of much of the loss of multi-year sea ice, and it continues to play a large role in the extinction of ice during the melt season. We present an analysis of the influence of satellite-derived ice surface temperature, ice thickness, albedo, and downwelling longwave/shortwave radiation as well as latitude and airborne snow depth estimates on the change in sea ice concentration in the Beaufort Sea from 2009 to 2016 using a Lagrangian tracking database. Results from this analysis indicate that parcels that melt during summer in the Beaufort Sea reside at lower latitudes and have lower ice thickness at the beginning of the melt season in most cases. The influence of sea ice thickness and snow depth observed by IceBridge offers less conclusive results, with some years exhibiting higher thicknesses/depths for melted parcels. Parcels that melted along IceBridge tracks do exhibit lower latitudes and ice thicknesses, however, which indicates that earlier melt and breakup of ice may contribute to a greater likelihood of extinction of parcels in the summer.

  2. Surface current observatons--Beaufort Sea, 1972

    Science.gov (United States)

    Barnes, Peter; Garlow, Richard

    1975-01-01

    Sediment transport via water and ice in the Beaufort Sea off northern Alaska is related to the movement of the surficial waters. As development proceeds along the north slope of alaska, a knowledge of the potential drift trajectories of water, ice, sediment and pollutants will be needed. In an attempt to better define the probable paths and rates of transport, 4200 surface drift cards were dropped during the U.S. Coast Guard WEBSEC cruise of August and September, 1972. The results of this release are the subject of this report. Because the data presented here will be used primarily by those interested in solving problems of transport, the emphasis has been placed on data presentation rather than a detailed analysis of the circulation. (Sinha-OEIS)

  3. Deglacial floods in the Beaufort Sea

    Science.gov (United States)

    Keigwin, L. D.; Driscoll, N. W.

    2014-12-01

    During summer 2013 USCGC Healy cruise 1302 surveyed and cored between Barrow, AK and the mouth of Amundsen Gulf, far to the east in the Beaufort Sea. Holocene deposition rates on the continental slope are high in the eastern Chukchi Sea and are lower farther east where deglacial sediments dominate. This is evident in CHIRP seismic data that trace two groups of reflectors as the sub-bottom depth between them increases. On the slope, at ~700 m w.d. near the mouth of the Mackenzie River, a pair of piston cores make a composite sequence 17 m long. The lower 4 m are sandy and capped by a maximum in magnetic susceptibility (ms) and a prominent reflector. N. pachyderma is too rare in this interval for 14C dates, but the d18-O of this species is as low as late Holocene. Above the reflector, counts of IRD are low, d18-O continues low, and the sediment is an acoustically transparent 7 m thick unit. The deepest date is 12.8 conv. 14C kyr at 13 m, and 3 overlying dates indicate the transparent unit accumulated at 8 m/14C kyr. The top of this unit is marked by the upper reflector that is in detail a triplet that corresponds to triple peaks in ms, grainsize, and IRD abundance. Between the two oldest sub-peaks of this reflector, d18-O reaches minimum values of ~1‰, or about 0.5‰ lower than late Holocene. In contrast to the deeper interval, this event is only 0.5 m thick and is dated to 11,050 conv. 14C kyr. Following this event, d18-O increases abruptly and then gradually decreases within the Holocene, more like a typical isotope stratigraphy. Overall, 9 dates indicate a gradual down-core increase in sedimentation rates from 9 cm/kyr in the late Holocene to the extreme of the deeper transparent unit with no age reversals. Using the modern Beaufort Sea Delta R (DR; 436 yrs), our oldest date calibrates to 13.8 ka, a little too old to be the cause of the Younger Dryas. However, the combined seismic, isotope, and sedimentological data suggest that at least the older transparent

  4. Heavy-mineral trends in the Beaufort Sea

    Science.gov (United States)

    Luepke, Gretchen

    1975-01-01

    Sediments of the Beaufort Sea, off the North Slope of Alaska contain a great variety of heavy minerals. These include garnet, chrome spinel, augite, pigionite, diopside, hornblende, enstatite, hypersthene, epidote, clinozoisite, zoisite, apatite, tourmaline, chloritoid, sphene, zircon, and opaque minerals. Much rarer constituents are glaucophane, lamprobolite, rutile, Kyanite, staurolite, and riebeckite. Garnet increases in abundance from east to west, which corresponds to a similar increase in garnet abundance in coastal outcrops of the Gubik Formation sands. Only garnet and iron-stained aggregates appear to have source-related distribution patterns. The other heavy minerals lack distinct distributive provinces, reflecting an environment dominated by intense mixing by ice-gouging and bioturbation and a homogenous source area. Waves and currents are not strong enough to sort sediments at depths greater than 10 m except during summer storms. The source of the Beaufort Sea heavy minerals is dominated by contributions from the Alaskan North Slope deposits of Tertiary and younger age. The Colville River, largest in the region, is probably the most influential in transporting sediments, but because of wave and current-mixing of sediments on the shelf, exact contributions from each river drainage cannot be ascertained. Coastal erosion of the Gubik Formation is probably at least as important as the Colville River in supplying heavy minerals to the Beaufort Sea. (Sinha-OEIS)

  5. Ice Draft and Ice Velocity Data in the Beaufort Sea, 1990-2003, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides measurement of sea ice draft (m) and the movement of sea ice (cm/s) over the continental shelf of the Eastern Beaufort Sea. The data set spans...

  6. Polar bear maternity denning in the Beaufort Sea

    Science.gov (United States)

    Amstrup, Steven C.; Gardner, Craig L.

    1994-01-01

    The distribution of polar bears (Ursus maritimus) is circumpolar in the NOrthern Hemisphere, but known locations of maternal dens are concentrated in relatively few, widely scattered locations. Denning is either uncommon or unknown within gaps. To understand effects of industrial development and propose increases in hunting, the temporal and spatial distribution of denning in the Beaufort Sea must be known. We caputred and radiocollared polar bears between 1981 and 1991 and determined tht denning in the Beaufort Sea region was sufficient to account for the estimated population there. Of 90 dend, 48 were on drifting pack ice, 38 on land, and 4 on land-fast ice. The portions of dens on land was higher (P= 0.029) in later compared with earlier years of the study. Bears denning on pack ice drifting as far as 997 km (x=385km) while in dens. there was no difference in cun production by bears denning on land and pack ice (P =0.66). Mean entry and exit dates were 11 November and 5 April for land dens and 22 November and 26 March for pack-ice dens. Female polar bears captured in the Beaufort Sea appeared to be isolated from those caught eat of Cape Bathurst in Canada. Of 35 polar bears that denned along the mainland coast of Alaska and Canada 80% denned between 137 00'W snf 146 59'W. Bears followed to >1 den did not reuse sites and consecutive dens were 20-1,304 km apart. However radio-collared bears are largely faithful to substrate (pack-ice, land, and land-fast ice) and the general geographic area of previous dens. Bears denning on land may be vunerable to human activities such as hunting and industrial development. However, predictable denning chronology and alck of site fidelity indicate that many potential impacts on denning polar bears could be mitigated.

  7. Recurring Spring Leads and Landfast Ice in the Beaufort and Chukchi Seas, 1993-2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In the Beaufort and Chukchi Seas, the most significant sea ice anomalies have occurred in the summer ice extent (Eicken et al. 2006). In addition, there has been a...

  8. Biophysical research requirements for Beaufort Sea hydrocarbon development

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-08-15

    This review identified biophysical research requirements and data gaps for the development of hydrocarbon resources in the Beaufort Sea. The potential major effects of critical activities during each phase of the offshore oil and gas development cycle were identified in order to assess the impacts on local communities and traditional harvesting methods. Baseline environmental conditions were established. Information needs were ranked using 3 criteria: (1) the current understanding of the biophysical component in terms of present status and long-term sustainability, (2) the potential impact of the oil and gas development on the long-term sustainability of the biophysical component, and (3) the timeline for completion of the research relative to the expected development for the Beaufort Sea region. Mitigation and environmental management plans were outlined, and key research, data collection, and data analyses required to address data gaps were identified. Previous gap analyses for the region were reviewed. Data from a series of workshops conducted with various stakeholders were also included in the study. High research priorities include the assessment of the effects of climatic change on the physical oceanography of the region, studies on deepwater plankton, benthos, and fish. It was concluded that studies are needed to determine the effects of development on marine mammals, avifauna, and macroalgae. 207 refs., 49 tabs., 4 figs.

  9. Effects of Mackenzie River Discharge and Bathymetry on Sea Ice in the Beaufort Sea

    Science.gov (United States)

    Nghiem, S. V.; Hall, D. K.; Rigor, I. G; Li, P.; Neumann, G.

    2014-01-01

    Mackenzie River discharge and bathymetry effects on sea ice in the Beaufort Sea are examined in 2012 when Arctic sea ice extent hit a record low. Satellite-derived sea surface temperature revealed warmer waters closer to river mouths. By 5 July 2012, Mackenzie warm waters occupied most of an open water area about 316,000 sq km. Surface temperature in a common open water area increased by 6.5 C between 14 June and 5 July 2012, before and after the river waters broke through a recurrent landfast ice barrier formed over the shallow seafloor offshore the Mackenzie Delta. In 2012, melting by warm river waters was especially effective when the strong Beaufort Gyre fragmented sea ice into unconsolidated floes. The Mackenzie and other large rivers can transport an enormous amount of heat across immense continental watersheds into the Arctic Ocean, constituting a stark contrast to the Antarctic that has no such rivers to affect sea ice.

  10. Ice Draft and Ice Velocity Data in the Beaufort Sea, 1990-2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set provides measurement of sea ice draft (m) and the movement of sea ice (cm/s) over the continental shelf of the Eastern Beaufort Sea. The data set spans...

  11. Habitat selection by two beluga whale populations in the Chukchi and Beaufort seas.

    Directory of Open Access Journals (Sweden)

    Donna D W Hauser

    Full Text Available There has been extensive sea ice loss in the Chukchi and Beaufort seas where two beluga whale (Delphinapterus leucas populations occur between July-November. Our goal was to develop population-specific beluga habitat selection models that quantify relative use of sea ice and bathymetric features related to oceanographic processes, which can provide context to the importance of changing sea ice conditions. We established habitat selection models that incorporated daily sea ice measures (sea ice concentration, proximity to ice edge and dense ice and bathymetric features (slope, depth, proximity to the continental slope, Barrow Canyon, and shore to establish quantitative estimates of habitat use for the Eastern Chukchi Sea ('Chukchi' and Eastern Beaufort Sea ('Beaufort' populations. We applied 'used v. available' resource selection functions to locations of 65 whales tagged from 1993-2012, revealing large variations in seasonal habitat selection that were distinct between sex and population groups. Chukchi whales of both sexes were predicted to use areas in close proximity to Barrow Canyon (typically <200 km as well as the continental slope in summer, although deeper water and denser ice were stronger predictors for males than females. Habitat selection differed more between sexes for Beaufort belugas. Beaufort males selected higher ice concentrations (≥40% than females (0-40% in July-August. Proximity to shore (<200 km strongly predicted summer habitat of Beaufort females, while distance to the ice edge was important for male habitat selection, especially during westward migration in September. Overall, our results indicate that sea ice variables were rarely the primary drivers of beluga summer-fall habitat selection. While diminished sea ice may indirectly affect belugas through changes in the ecosystem, associations with bathymetric features that affect prey availability seemed key to habitat selection during summer and fall. These results

  12. Pigment signatures of phytoplankton communities in the Beaufort Sea

    Science.gov (United States)

    Coupel, P.; Matsuoka, A.; Ruiz-Pino, D.; Gosselin, M.; Marie, D.; Tremblay, J.-É.; Babin, M.

    2015-02-01

    Phytoplankton are expected to respond to recent environmental changes of the Arctic Ocean. In terms of bottom-up control, modifying the phytoplankton distribution will ultimately affect the entire food web and carbon export. However, detecting and quantifying changes in phytoplankton communities in the Arctic Ocean remains difficult because of the lack of data and the inconsistent identification methods used. Based on pigment and microscopy data sampled in the Beaufort Sea during summer 2009, we optimized the chemotaxonomic tool CHEMTAX (CHEMical TAXonomy) for the assessment of phytoplankton community composition in an Arctic setting. The geographical distribution of the main phytoplankton groups was determined with clustering methods. Four phytoplankton assemblages were determined and related to bathymetry, nutrients and light availability. Surface waters across the whole survey region were dominated by prasinophytes and chlorophytes, whereas the subsurface chlorophyll maximum was dominated by the centric diatoms Chaetoceros socialis on the shelf and by two populations of nanoflagellates in the deep basin. Microscopic counts showed a high contribution of the heterotrophic dinoflagellates Gymnodinium and Gyrodinium spp. to total carbon biomass, suggesting high grazing activity at this time of the year. However, CHEMTAX was unable to detect these dinoflagellates because they lack peridinin. In heterotrophic dinoflagellates, the inclusion of the pigments of their prey potentially leads to incorrect group assignments and some misinterpretation of CHEMTAX. Thanks to the high reproducibility of pigment analysis, our results can serve as a baseline to assess change and spatial or temporal variability in several phytoplankton populations that are not affected by these misinterpretations.

  13. Coastal Environment, Bathymetry and Physical Oceanography along the Beaufort, Chukchi and Bering Seas.

    Science.gov (United States)

    1980-01-01

    Some character: tics of the Beaufort Sea shelf current: Journal of Geophysical Research, vol. 80, no. 24, p. 3465-3468. 30. Ostenso, N.A., 1966, Beaufort...8217~~ ...... ’<.... " 3o 1990 op 8,o CIL .1i 4 /C "Ŕ .J0 -E ,KItoC,, - f -L Fig r 31 .Wave - . _," el height/ disod (ohzrou) oero ;- ( ro Beauo r Sea ref 2...Wright, L.D. 1973. Alaskan arc- tic coastaZ pro, esaes scd morphology. Louisiana State University, Cczs:al Studies Institute, Technical Peport No. 149

  14. Beaufort Sea planning area oil and gas Lease Sale 170. Final environmental impact statement

    International Nuclear Information System (INIS)

    1998-02-01

    This environmental impact statement (EIS) assesses Lease Sale 170 proposed for August 1998 and comprised of 363 lease blocks in the Beaufort Sea planning area. The analysis addresses the significant environmental and socioeconomic concerns identified in the scoping process. Scoping consisted of input from State and Federal agencies, the petroleum industry, Native groups, environmental and public interest groups, and concerned individuals. The potential effects expected from the interaction between environmental resources and OCS-related activities were determined with respect to available scientific information and traditional knowledge. This EIS incorporates information from the Final EIS for the Beaufort Sea OCS Sale 144 (USD01, MMS, 1996a)

  15. Arctic Storms and Their Influence on Surface Climate in the Chukchi-Beaufort Seas

    Science.gov (United States)

    Yang, Y.; Zhang, X.; Rinke, A.; Zhang, J.

    2017-12-01

    Increases in the frequency and intensity of Arctic storms and resulting weather hazards may endanger the offshore environment, coastal community, and energy infrastructure in the Arctic as sea ice retreats. Advancing ability to identify fine-scale variations in surface climate produced by progressively stronger storm would be extremely helpful to resources management and sustainable development for coastal community. In this study, we analyzed the storms and their impacts on surface climate over the Beaufort-Chukchi seas by employing the date sets from both the hindcast simulations of the coupled Arctic regional climate model HIRHAM-NAOSIM and the recently developed Chukchi-Beaufort High-resolution Atmospheric Reanalysis (CBHAR). Based on the characteristics of spatial pattern and temporal variability of the Arctic storm activity, we categorized storms to three groups with their different origins: the East Siberia Sea, Alaska and the central Arctic Ocean. The storms originating from the central Arctic Ocean have the strongest intensity in winter with relatively less storm number. Storms traveling from Alaska to the Beaufort Sea most frequently occurred in autumn with weaker intensity. A large portion of storms originated from the East Siberia Sea region in summer. Further statistical analysis suggests that increase in surface air temperature and wind speed could be attributed to the increased frequency of storm occurrence in autumn (September to November) along the continental shelf in the Beaufort Sea.

  16. Polar bear population dynamics in the southern Beaufort Sea during a period of sea ice decline

    Science.gov (United States)

    Bromaghin, Jeffrey F.; McDonald, Trent L.; Stirling, Ian; Derocher, Andrew E.; Richardson, Evan S.; Regehr, Eric V.; Douglas, David C.; Durner, George M.; Atwood, Todd C.; Amstrup, Steven C.

    2015-01-01

    In the southern Beaufort Sea of the United States and Canada, prior investigations have linked declines in summer sea ice to reduced physical condition, growth, and survival of polar bears (Ursus maritimus). Combined with projections of population decline due to continued climate warming and the ensuing loss of sea ice habitat, those findings contributed to the 2008 decision to list the species as threatened under the U.S. Endangered Species Act. Here, we used mark–recapture models to investigate the population dynamics of polar bears in the southern Beaufort Sea from 2001 to 2010, years during which the spatial and temporal extent of summer sea ice generally declined. Low survival from 2004 through 2006 led to a 25–50% decline in abundance. We hypothesize that low survival during this period resulted from (1) unfavorable ice conditions that limited access to prey during multiple seasons; and possibly, (2) low prey abundance. For reasons that are not clear, survival of adults and cubs began to improve in 2007 and abundance was comparatively stable from 2008 to 2010, with ~900 bears in 2010 (90% CI 606–1212). However, survival of subadult bears declined throughout the entire period. Reduced spatial and temporal availability of sea ice is expected to increasingly force population dynamics of polar bears as the climate continues to warm. However, in the short term, our findings suggest that factors other than sea ice can influence survival. A refined understanding of the ecological mechanisms underlying polar bear population dynamics is necessary to improve projections of their future status and facilitate development of management strategies.

  17. Bowhead whale body condition and links to summer sea ice and upwelling in the Beaufort Sea

    Science.gov (United States)

    George, John C.; Druckenmiller, Matthew L.; Laidre, Kristin L.; Suydam, Robert; Person, Brian

    2015-08-01

    We examined the response of bowhead whale (Balaena mysticetus) body condition to summer sea ice conditions and upwelling-favorable winds. We used a long-term dataset collected from whales of the Bering-Chukchi-Beaufort Seas (BCB) stock to estimate various body condition indices (BCI's) for individual whales that were harvested by Alaskan Eskimos. A series of offshore regions frequented by bowhead whales in summer were delineated and used to quantify interannual summertime environmental conditions including: (a) mean open water fraction, (b) duration of melt season, (c) date of continuous freeze-up, and (d) mean upwelling-favorable wind stress. Body condition was analyzed relative to these metrics for both the preceding summer feeding season and the previous three seasons combined. Our analysis indicates a significant increase in the long-term trend in an axillary girth-based body condition index (BCIG) over the study period (1989-2011). The increase in BCIG is likely associated with the trend in overall reduction of sea ice, including increased duration of open water, changes in upwelling potential (wind stress), and possibly higher primary production in the Pacific Arctic marine ecosystem favoring water-column invertebrates. We found strong significant positive correlations between BCIG and late summer open water fraction in the Beaufort Sea and smaller nearshore areas off the Mackenzie Delta and west of Banks Island. Additionally, BCIG was positively and significantly correlated with duration of melt season, later date of freeze-up in the Beaufort Sea, and upwelling-favorable winds on the Mackenzie shelf and west of Banks Island. A strong seasonal difference in BCI's was noted for subadult bowheads, presumably associated with summer feeding; however, yearlings were found to drop in BCI over at least the first summer after weaning. Our results indicate an overall increase in bowhead whale body condition and a positive correlation with summer sea ice loss over the

  18. A Possible Link Between Winter Arctic Sea Ice Decline and a Collapse of the Beaufort High?

    Science.gov (United States)

    Petty, Alek A.

    2018-03-01

    A new study by Moore et al. (2018, https://doi.org/10.1002/2017GL076446) highlights a collapse of the anticyclonic "Beaufort High" atmospheric circulation over the western Arctic Ocean in the winter of 2017 and an associated reversal of the sea ice drift through the southern Beaufort Sea (eastward instead of the predominantly westward circulation). The authors linked this to the loss of sea ice in the Barents Sea, anomalous warming over the region, and the intrusion of low-pressure cyclones along the eastern Arctic. In this commentary we discuss the significance of this observation, the challenges associated with understanding these possible linkages, and some of the alternative hypotheses surrounding the impacts of winter Arctic sea ice loss.

  19. Statistical Aspects of Ice Gouging on the Alaskan Shelf of the Beaufort Sea,

    Science.gov (United States)

    1983-09-01

    can be useful, it grams, dise obser\\ations, and repetitis e track- should not be combined wsith the data on gouges lines) that both gouge depths and...Detcison for Civil L niraneers. Mathew~s, J.B. (19811) Obsersations of surface and Ne\\As York: Mecira%%-Hill. 684 pp. bottom current’s in the Beaufort Sea

  20. Trace metal contamination of Beaufort's Dyke, North Channel, Irish Sea: A legacy of ordnance disposal

    International Nuclear Information System (INIS)

    Callaway, Alexander; Quinn, Rory; Brown, Craig J.; Service, Matthew; Benetti, Sara

    2011-01-01

    Highlights: → Our samples are the first trace metal concentrations taken from the valley of Beaufort's Dyke. → There is no clear trend between concentrations of trace metals in Dyke and NMMP sediments. → Particle transport simulations show dispersal of trace metals from Beaufort's Dyke is possible. → Disposed ordnance may also contribute to contamination of surrounding areas. → These methods could help predict areas at risk of future trace metal contamination as a result of ordnance disposal. - Abstract: Beaufort's Dyke is a disused ordnance disposal ground within the North Channel of the Irish Sea. Over 1 million tonnes of ordnance were disposed of in the dyke over a 40 year period representing a substantial volume of trace metal pollutants introduced to the seabed. Utilising particle transport modelling software we simulated the potential transport of metal particles from Beaufort's Dyke over a 3 month period. This demonstrated that Beaufort's Dyke has the potential to act as a source for trace metal contamination to areas beyond the submarine valley. Trace metal analysis of sediments from the Dyke and surrounding National Marine Monitoring Programme areas demonstrate that the Dyke is not the most contaminated site in the region. Particle transport modelling enables the transport pathways of trace metal contaminants to be predicted. Implementation of the technique in other munitions disposal grounds will provide valuable information for the selection of monitoring stations.

  1. Collapse of the 2017 Winter Beaufort High: A Response to Thinning Sea Ice?

    Science.gov (United States)

    Moore, G. W. K.; Schweiger, A.; Zhang, J.; Steele, M.

    2018-03-01

    The winter Arctic atmosphere is under the influence of two very different circulation systems: extratropical cyclones travel along the primary North Atlantic storm track from Iceland toward the eastern Arctic, while the western Arctic is characterized by a quasi-stationary region of high pressure known as the Beaufort High. The winter (January through March) of 2017 featured an anomalous reversal of the normally anticyclonic surface winds and sea ice motion in the western Arctic. This reversal can be traced to a collapse of the Beaufort High as the result of the intrusion of low-pressure systems from the North Atlantic, along the East Siberian Coast, into the Arctic Basin. Thin sea ice as the result of an extremely warm autumn (October through December) of 2016 contributed to the formation of an anomalous thermal low over the Barents Sea that, along with a northward shift of the tropospheric polar vortex, permitted this intrusion. The collapse of the Beaufort High during the winter of 2017 was associated with simultaneous 2-sigma sea level pressure, surface wind, and sea ice circulation anomalies in the western Arctic. As the Arctic sea ice continues to thin, such reversals may become more common and impact ocean circulation, sea ice, and biology.

  2. Microsatellite DNA and mitochondrial DNA variation in polar bears (Ursus maritimus) from the Beaufort and Chukchi seas, Alaska

    Science.gov (United States)

    Cronin, M.A.; Amstrup, Steven C.; Scribner, K.T.

    2006-01-01

    Radiotelemetry data have shown that polar bears (Ursus maritimus Phipps, 1774) occur in separate subpopulations in the Chukchi Sea and the southern Beaufort Sea. However, segregation is not absolute, and there is overlap of ranges of animals in each subpopulation. We used genetic variation at eight microsatellite DNA loci and mitochondrial DNA (mtDNA) to further assess the degree of spatial structure of polar bears from the Chukchi and southern Beaufort seas. Microsatellite allele frequencies and mtDNA haplotype frequencies of bears from the southern Beaufort and Chukchi seas did not differ significantly. Lack of differentiation at both maternally inherited mtDNA and bi-parentally inherited microsatellite loci suggests that gene flow between the two areas is mediated by both sexes. The genetic data indicate that polar bears in the southern Beaufort and Chukchi seas compose one interbreeding population. However, there is considerable fidelity to ranges in each area, particularly by adult females. The combined genetic and movement data suggest that polar bears could be managed as Beaufort Sea and Chukchi Sea subpopulations of a combined southern Beaufort Sea and Chukchi Sea population. ?? 2006 NRC.

  3. Survival and breeding of polar bears in the southern Beaufort Sea in relation to sea ice

    Science.gov (United States)

    Regehr, E.V.; Hunter, C.M.; Caswell, H.; Amstrup, Steven C.; Stirling, I.

    2010-01-01

    1. Observed and predicted declines in Arctic sea ice have raised concerns about marine mammals. In May 2008, the US Fish and Wildlife Service listed polar bears (Ursus maritimus) - one of the most ice-dependent marine mammals - as threatened under the US Endangered Species Act. 2. We evaluated the effects of sea ice conditions on vital rates (survival and breeding probabilities) for polar bears in the southern Beaufort Sea. Although sea ice declines in this and other regions of the polar basin have been among the greatest in the Arctic, to date population-level effects of sea ice loss on polar bears have only been identified in western Hudson Bay, near the southern limit of the species' range. 3. We estimated vital rates using multistate capture-recapture models that classified individuals by sex, age and reproductive category. We used multimodel inference to evaluate a range of statistical models, all of which were structurally based on the polar bear life cycle. We estimated parameters by model averaging, and developed a parametric bootstrap procedure to quantify parameter uncertainty. 4. In the most supported models, polar bear survival declined with an increasing number of days per year that waters over the continental shelf were ice free. In 2001-2003, the ice-free period was relatively short (mean 101 days) and adult female survival was high (0 ∙ 96-0 ∙ 99, depending on reproductive state). In 2004 and 2005, the ice-free period was longer (mean 135 days) and adult female survival was low (0 ∙ 73-0 ∙ 79, depending on reproductive state). Breeding rates and cub litter survival also declined with increasing duration of the ice-free period. Confidence intervals on vital rate estimates were wide. 5. The effects of sea ice loss on polar bears in the southern Beaufort Sea may apply to polar bear populations in other portions of the polar basin that have similar sea ice dynamics and have experienced similar, or more severe, sea ice declines. Our findings

  4. Survival and breeding of polar bears in the southern Beaufort Sea in relation to sea ice.

    Science.gov (United States)

    Regehr, Eric V; Hunter, Christine M; Caswell, Hal; Amstrup, Steven C; Stirling, Ian

    2010-01-01

    1. Observed and predicted declines in Arctic sea ice have raised concerns about marine mammals. In May 2008, the US Fish and Wildlife Service listed polar bears (Ursus maritimus) - one of the most ice-dependent marine mammals - as threatened under the US Endangered Species Act. 2. We evaluated the effects of sea ice conditions on vital rates (survival and breeding probabilities) for polar bears in the southern Beaufort Sea. Although sea ice declines in this and other regions of the polar basin have been among the greatest in the Arctic, to date population-level effects of sea ice loss on polar bears have only been identified in western Hudson Bay, near the southern limit of the species' range. 3. We estimated vital rates using multistate capture-recapture models that classified individuals by sex, age and reproductive category. We used multimodel inference to evaluate a range of statistical models, all of which were structurally based on the polar bear life cycle. We estimated parameters by model averaging, and developed a parametric bootstrap procedure to quantify parameter uncertainty. 4. In the most supported models, polar bear survival declined with an increasing number of days per year that waters over the continental shelf were ice free. In 2001-2003, the ice-free period was relatively short (mean 101 days) and adult female survival was high (0.96-0.99, depending on reproductive state). In 2004 and 2005, the ice-free period was longer (mean 135 days) and adult female survival was low (0.73-0.79, depending on reproductive state). Breeding rates and cub litter survival also declined with increasing duration of the ice-free period. Confidence intervals on vital rate estimates were wide. 5. The effects of sea ice loss on polar bears in the southern Beaufort Sea may apply to polar bear populations in other portions of the polar basin that have similar sea ice dynamics and have experienced similar, or more severe, sea ice declines. Our findings therefore are

  5. Temperature, salinity, and other data from buoy casts in the Arctic Ocean, Barents Sea and Beaufort Sea from 1948 to 1993 (NODC Accession 9800040)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, and other data were collected using buoy casts in the Arctic Ocean, Barents Sea and Beaufort Sea from 1948 to 1993. Data were collected by the...

  6. SBI AWS02-I CTD Data collected from the Polar Star in the Beaufort and Chukchi Seas (NODC Accession 0001290)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The field phase of the Shelf-Basin Interactions Experiment (SBI) began in 2002 with a series of three cruises to the Chukchi and Beaufort Seas. SBI is a...

  7. EFFLUENT - DISCHARGE DESCRIPTION and Other Data from NOAA LAUNCHES From Beaufort Sea from 19890804 to 19890820 (NODC Accession 9100109)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The chemical data in this accession was collected as part of the the Beaufort Sea Monitoring Program. The data was collected between August 4 and August 20, 1989...

  8. AFSC/NMML: Passive acoustic sonobuoy recordings from Bering, Chukchi, and Beaufort Seas in Alaska, 2007-2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Mammal Laboratory (NMML) has conducted passive acoustic monitoring in the Bering, Chukchi, and Western Beaufort Seas to determine spatio-temporal...

  9. Toward a Predictive Model of Arctic Coastal Retreat in a Warming Climate, Beaufort Sea, Alaska

    Science.gov (United States)

    2012-09-30

    resulting from climate change. Our study is focused on the Beaufort Sea coast within the National Petroleum Reserve – Alaska (NPR-A), approximately...published in Computers in Geosciences . In this paper we introduce our model of the thermal impact of thaw lakes on the permafrost of the North Slope...F. E. Urban, and G. D. Clow, 2011, Modeling the subsurface thermal impact of Arctic thaw lakes in a warming climate. Computers & Geosciences (2011

  10. The delivery of mercury to the Beaufort Sea of the Arctic Ocean by the Mackenzie River.

    Science.gov (United States)

    Leitch, Daniel R; Carrie, Jesse; Lean, David; Macdonald, Robie W; Stern, Gary A; Wang, Feiyue

    2007-02-01

    Very high levels of mercury (Hg) have recently been reported in marine mammals and other higher trophic-level biota in the Mackenzie Delta and Beaufort Sea of the western Arctic Ocean. To quantify the input of Hg (particulate, dissolved and methylated) by the Mackenzie River as a potential source for Hg in the ecosystem, surface water and sediment samples were taken from 79 sites in the lower Mackenzie Basin during three consecutive summers (2003-2005) and analyzed for Hg and methylmercury (MeHg). Intensive studies were also carried out in the Mackenzie Delta during the freshets of 2004 and 2005. Large seasonal and annual variations were found in Hg concentrations in the river, coincident with the variations in water discharge. Increased discharges during spring freshet and during the summers of 2003 and 2005 compared to 2004 were mirrored by higher Hg concentrations. The correlation between Hg concentration and riverflow suggests additional Hg sources during periods of high water, potentially from increased surface inundation and increased bank erosion. The increase in the Hg concentration with increasing water discharge amplifies the annual Hg and MeHg fluxes during high water level years. For the period 2003-2005, the Hg and MeHg fluxes from the Mackenzie River to the Beaufort Sea averaged 2.2 tonnes/yr and 15 kg/yr, respectively, the largest known Hg source to the Beaufort Sea. More than half of the mercury flux occurs during the short spring freshet season which coincides with the period of rapid growth of marine biota. Consequently, the Mackenzie River input potentially provides the major mercury source to marine mammals of the Beaufort Sea. The Hg and MeHg fluxes from the Mackenzie River are expected to further increase with the projected climate warming in the Mackenzie Basin.

  11. Recent observations of intraspecific predation and cannibalism among polar bears in the southern Beaufort Sea

    Science.gov (United States)

    Amstrup, Steven C.; Stirling, I.; Smith, T.S.; Perham, C.; Thiemann, G.W.

    2006-01-01

    Intraspecific killing has been reported among polar bears (Ursus maritimus), brown bears (U. arctos), and black bears (U. americanus). Although cannibalism is one motivation for such killings, the ecological factors mediating such events are poorly understood. Between 24 January and 10 April 2004, we confirmed three instances of intraspecific predation and cannibalism in the Beaufort Sea. One of these, the first of this type ever reported for polar bears, was a parturient female killed at her maternal den. The predating bear was hunting in a known maternal denning area and apparently discovered the den by scent. A second predation event involved an adult female and cub recently emerged from their den, and the third involved a yearling male. During 24 years of research on polar bears in the southern Beaufort Sea region of northern Alaska and 34 years in northwestern Canada, we have not seen other incidents of polar bears stalking, killing, and eating other polar bears. We hypothesize that nutritional stresses related to the longer ice-free seasons that have occurred in the Beaufort Sea in recent years may have led to the cannibalism incidents we observed in 2004. ?? Springer-Verlag 2006.

  12. Regional-Scale Variability of Macrofauna Species Assemblages and Environmental Drivers in the Canadian Beaufort Sea

    Science.gov (United States)

    Majewski, A.; MacPhee, S.; de Montety, L.; Reist, J.; Archambault, P.

    2016-02-01

    Appropriate marine spatial planning is needed to address pressures associated with climate change, resource exploration and increased shipping in the Canadian Beaufort Sea. Information regarding the spatial variability of species assemblages and the factors that structure them are required, for example, in designing networks of marine protected areas and establishing reference conditions for assessing anthropogenic activities anticipated to have regional-scale effects. Benthic macrofauna have been widely applied as ecological indicators in many marine regions because they are relatively sessile, long-lived, and respond to environmental gradients in a predictable manner. Recently, significant progress has been made toward reporting Arctic macrofaunal biodiversity baselines across large spatial scales (i.e. pan-Arctic, Canadian Arctic) and at local-scales within the Beaufort Sea around specific geographic features (e.g., Beaufort Shelf, polynyas and areas of upwelling, lease blocks). Systematic, regional-scale surveys, however, remain a gap. Benthic ecosystem components were sampled across a broad depth range (20 - 1500m) from the transboundary region of the Yukon-Alaska border into Amundsen Gulf, and multivariate analyses of these novel survey data characterize spatial variability in macrobenthic community structure. Relationships between species assemblages and environmental drivers including depth, bottom type (e.g., granulometry), water mass characteristics (e.g., temperature, salinity) and benthic food proxies (e.g., %organic matter, benthic chlorophyll concentration) were examined. This regional-scale approach based on a systematic, transect-based survey design covers a significant portion of the Canadian Beaufort Sea and expands existing biodiversity baselines to deeper sites beyond the continental shelf break. This work has direct application to developing predictive models, habitat maps and biotic indicators for monitoring.

  13. Wind–sea surface temperature–sea ice relationship in the Chukchi–Beaufort Seas during autumn

    Science.gov (United States)

    Zhang, Jing; Stegall, Steve T.; Zhang, Xiangdong

    2018-03-01

    Dramatic climate changes, especially the largest sea ice retreat during September and October, in the Chukchi–Beaufort Seas could be a consequence of, and further enhance, complex air–ice–sea interactions. To detect these interaction signals, statistical relationships between surface wind speed, sea surface temperature (SST), and sea ice concentration (SIC) were analyzed. The results show a negative correlation between wind speed and SIC. The relationships between wind speed and SST are complicated by the presence of sea ice, with a negative correlation over open water but a positive correlation in sea ice dominated areas. The examination of spatial structures indicates that wind speed tends to increase when approaching the ice edge from open water and the area fully covered by sea ice. The anomalous downward radiation and thermal advection, as well as their regional distribution, play important roles in shaping these relationships, though wind-driven sub-grid scale boundary layer processes may also have contributions. Considering the feedback loop involved in the wind–SST–SIC relationships, climate model experiments would be required to further untangle the underlying complex physical processes.

  14. Sea ice circulation around the Beaufort Gyre: The changing role of wind forcing and the sea ice state

    Science.gov (United States)

    Petty, Alek A.; Hutchings, Jennifer K.; Richter-Menge, Jacqueline A.; Tschudi, Mark A.

    2016-05-01

    Sea ice drift estimates from feature tracking of satellite passive microwave data are used to investigate seasonal trends and variability in the ice circulation around the Beaufort Gyre, over the multidecadal period 1980-2013. Our results suggest an amplified response of the Beaufort Gyre ice circulation to wind forcing, especially during the late 2000s. We find increasing anticyclonic ice drift across all seasons, with the strongest trend in autumn, associated with increased ice export out of the southern Beaufort Sea (into the Chukchi Sea). A flux gate analysis highlights consistency across a suite of drift products. Despite these seasonal anticyclonic ice drift trends, a significant anticyclonic wind trend occurs in summer only, driven, in-part, by anomalously anticyclonic winds in 2007. Across all seasons, the ice drift curl is more anticyclonic than predicted from a linear relationship to the wind curl in the 2000s, compared to the 1980s/1990s. The strength of this anticyclonic ice drift curl amplification is strongest in autumn and appears to have increased since the 1980s (up to 2010). In spring and summer, the ice drift curl amplification occurs mainly between 2007 and 2010. These results suggest nonlinear ice interaction feedbacks (e.g., a weaker, more mobile sea ice pack), enhanced atmospheric drag, and/or an increased role of the ocean. The results also show a weakening of the anticyclonic wind and ice circulation since 2010.

  15. A year in the acoustic world of bowhead whales in the Bering, Chukchi and Beaufort seas

    Science.gov (United States)

    Clark, Christopher W.; Berchok, Catherine L.; Blackwell, Susanna B.; Hannay, David E.; Jones, Josh; Ponirakis, Dimitri; Stafford, Kathleen M.

    2015-08-01

    Bowhead whales, Balaena mysticetus, in the Bering-Chukchi-Beaufort (BCB) population, experience a variable acoustic environment among the regions they inhabit throughout the year. A total of 41,698 h of acoustic data were recorded from 1 August 2009 through 4 October 2010 at 20 sites spread along a 2300 km transect from the Bering Sea to the southeast Beaufort Sea. These data represent the combined output from six research teams using four recorder types. Recorders sampled areas in which bowheads occur and in which there are natural and anthropogenic sources producing varying amounts of underwater noise. We describe and quantify the occurrence of bowheads throughout their range in the Bering, Chukchi, and Beaufort seas over a 14-month period by aggregating our acoustic detections of bowhead whale sounds. We also describe the spatial-temporal variability in the bowhead acoustic environment using sound level measurements within a frequency band in which their sounds occur, by dividing a year into three, 4-month seasons (Summer-Fall 2009, August-November 2009: Winter 2009-2010, December 2009-March 2010: and Spring-Summer 2010, April-July 2010) and their home range into five zones. Statistical analyses revealed no significant relationship between acoustic occurrence, distance offshore, and water depth during Summer-Fall 2009, but there was a significant relationship during Spring-Summer 2010. A continuous period with elevated broadband sound levels lasting ca. 38 days occurred in the Bering Sea during the Winter 2009-2010 season as a result of singing bowheads, while a second period of elevated levels lasting at least 30 days occurred during the early spring-summer season as a result of singing bearded seals. The lowest noise levels occurred in the Chukchi Sea from the latter part of November into May. In late summer 2009 very faint sounds from a seismic airgun survey approximately 700 km away in the eastern Beaufort Sea were detected on Chukchi recorders. Throughout

  16. Arctic continental shelf morphology related to sea-ice zonation, Beaufort Sea, Alaska

    Science.gov (United States)

    Reimnitz, E.; Toimil, L.; Barnes, P.

    1978-01-01

    Landsat-1 and NOAA satellite imagery for the winter 1972-1973, and a variety of ice and sea-floor data were used to study sea-ice zonation and dynamics and their relation to bottom morphology and geology on the Beaufort Sea continental shelf of arctic Alaska. In early winter the location of the boundary between undeformed fast ice and westward-drifting pack ice of the Pacific Gyre is controlled by major coastal promontories. Pronounced linear pressure- and shear-ridges, as well as hummock fields, form along this boundary and are stabilized by grounding, generally between the 10- and 20-m isobaths. Slippage along this boundary occurs intermittently at or seaward of the grounded ridges, forming new grounded ridges in a widening zone, the stamukhi zone, which by late winter extends out to the 40-m isobath. Between intermittent events along the stamukhi zone, pack-ice drift and slippage is continuous along the shelf edge, at average rates of 3-10 km/day. Whether slippage occurs along the stamukhi zone or along the shelf edge, it is restricted to a zone several hundred meters wide, and ice seaward of the slip face moves at uniform rates without discernible drag effects. A causal relationship is seen between the spatial distribution of major ice-ridge systems and offshore shoals downdrift of major coastal promontories. The shoals appear to have migrated shoreward under the influence of ice up to 400 m in the last 25 years. The sea floor seaward of these shoals within the stamukhi zone shows high ice-gouge density, large incision depths, and a high degree of disruption of internal sedimentary structures. The concentration of large ice ridges and our sea floor data in the stamukhi zone indicate that much of the available marine energy is expended here, while the inner shelf and coast, where the relatively undeformed fast ice grows, are sheltered. There is evidence that anomalies in the overall arctic shelf profile are related to sea-ice zonation, ice dynamics, and bottom

  17. Variation in winter diet of southern Beaufort Sea polar bears inferred from stable isotope analysis

    Science.gov (United States)

    Bentzen, T.W.; Follmann, Erich H.; Amstrup, Steven C.; York, G.S.; Wooller, M.J.; O'Hara, T. M.

    2007-01-01

    Ringed seals (Phoca hispida Schreber, 1775 = Pusa hispida (Schreber, 1775)) and bearded seals (Erignathus barbatus (Erxleben, 1777)) represent the majority of the polar bear (Ursus maritimus Phipps, 1774) annual diet. However, remains of lower trophic level bowhead whales (Balaena mysticetus L., 1758) are available in the southern Beaufort Sea and their dietary contribution to polar bears has been unknown. We used stable isotope (13C/12C, δ13C, 15N/14N, and δ15N) analysis to determine the diet composition of polar bears sampled along Alaska’s Beaufort Sea coast in March and April 2003 and 2004. The mean δ15N values of polar bear blood cells were 19.5‰ (SD = 0.7‰) in 2003 and 19.9‰ (SD = 0.7‰) in 2004. Mixing models indicated bowhead whales composed 11%–26% (95% CI) of the diets of sampled polar bears in 2003, and 0%–14% (95% CI) in 2004. This suggests significant variability in the proportion of lower trophic level prey in polar bear diets among individuals and between years. Polar bears depend on sea ice for hunting seals, and the temporal and spatial availabilities of sea ice are projected to decline. Consumption of low trophic level foods documented here suggests bears may increasingly scavenge such foods in the future.

  18. Minimum distribution of subsea ice-bearing permafrost on the US Beaufort Sea continental shelf

    Science.gov (United States)

    Brothers, Laura L.; Hart, Patrick E.; Ruppel, Carolyn D.

    2012-01-01

    Starting in Late Pleistocene time (~19 ka), sea level rise inundated coastal zones worldwide. On some parts of the present-day circum-Arctic continental shelf, this led to flooding and thawing of formerly subaerial permafrost and probable dissociation of associated gas hydrates. Relict permafrost has never been systematically mapped along the 700-km-long U.S. Beaufort Sea continental shelf and is often assumed to extend to ~120 m water depth, the approximate amount of sea level rise since the Late Pleistocene. Here, 5,000 km of multichannel seismic (MCS) data acquired between 1977 and 1992 were examined for high-velocity (>2.3 km s−1) refractions consistent with ice-bearing, coarse-grained sediments. Permafrost refractions were identified along sea ice-bearing permafrost, which does not extend seaward of 30 km offshore or beyond the 20 m isobath.

  19. Origin and fate of particulate organic matter in the southern Beaufort Sea - Amundsen Gulf region, Canadian Arctic

    DEFF Research Database (Denmark)

    Magen, Cedric; Chaillou, Gwenaelle; Crowe, Sean

    2010-01-01

    To establish the relative importance of terrigenous and marine organic matter in the southern Beaufort Sea, we measured the concentrations and the stable isotopic compositions of organic carbon and total nitrogen in sediments and in settling particles intercepted by sediment traps. The organic...... carbon content of surface! sediment in the Chukchi and southern Beaufort Seas ranged from 0.6 to 1.6% dry wt., without a clear geographical pattern. The C-ORG:N-TOT ratio ranged from 7.0 to 10.4 and did not vary significantly downcore at any one station. Values delta C-13(ORG) and delta N-15(TOT...... from and much more variable than in the bottom sediments. The isotopic signature of organic matter in the Beaufort Sea is well constrained by three distinct end-members: a labile marine component produced in situ by planktonic organisms, a refractory marine component, the end product of respiration...

  20. Synoptic weather conditions, clouds, and sea ice in the Beaufort and Chukchi Seasonal Ice Zone

    Science.gov (United States)

    Liu, Z.; Schweiger, A. J. B.

    2017-12-01

    The connections between synoptic conditions and clouds and sea ice over the Beaufort and Chukchi Seasonal Ice Zone are examined. Four synoptic states with distinct thermodynamic and dynamic spatial and vertical signatures are identified using a k-means classification algorithm and the ERA-Interim reanalysis data from 1979 to 2014. The combined CloudSat and Calipso cloud observations suggest control of clouds by synoptic states. Warm continental air advection is associated with the fewest low-level clouds, cold air advection under low pressure generates the most low-level clouds. Low-level cloud fractions are related to lower-tropospheric stability and both are regulated by synoptic conditions. Observed cloud vertical and spatial variability is reproduced well in ERA-Interim, but winter low-level cloud fraction is overestimated. Sea ice melt onset is related to synoptic conditions. Melt onsets occur more frequently and earlier with warm air advection states. The warm continental air advection state with the highest temperature is the most favorable for melt onsets even though fewer low-level clouds are associated with this state. The other warm advection state is cloudier but colder. In the Beaufort and Chukchi Seasonal Ice Zone, the much higher temperature and total column water of the warm continental air advection state compensate the smaller cloud longwave radiative fluxes due to the smaller low-level cloud fraction. In addition, the higher shortwave radiative fluxes and turbulent fluxes to the surface are also favorable for sea ice melt onset.

  1. Marine Arctic Ecosystem Study (MARES) - An Integrated Approach to the Dynamics of the Beaufort Sea

    Science.gov (United States)

    Wiese, F. K.; Gryba, R.; Kelly, B. P.

    2016-02-01

    MARES is an integrated ecosystem research initiative coordinated and planned by the Bureau of Ocean Energy Management, the Office of Naval Research, the National Aeronautics and Space Administration, the U.S. Coast Guard, and Shell through the National Oceanographic Partnership Program. The overarching goal is to advance our knowledge of the structure and function of the Beaufort Sea marine ecosystem so as to link atmospheric and oceanic drivers to sea ice patterns and marine mammal distribution and availability to local subsistence communities. The study, funded in 2014, focuses on the marine ecosystem along the Beaufort Sea shelf from Barrow, Alaska to the Mackenzie River delta in Canada and is scheduled to include bio-physical moorings along the US-Canadian border, glider deployments packed with bio-physical sensors, tagging of whales and ice-associated seals with satellite CTD-Fluorometer tags, biophysical and chemical cruises including the measurement and characterization of hydrography, ice, nutrients, primary and secondary production, carbon budgets, benthic fauna, fish, as well as analysis of freshwater input and chemical loadings, and ecosystem modeling. This presentation will focus on preliminary results from the ice seal tagging that started in the summer of 2015 and describe some of the planning and possibilities for partnerships for the more comprehensive 2016 field season and beyond.

  2. Climate change and ice hazards in the Beaufort Sea

    DEFF Research Database (Denmark)

    Barber, D. G.; McCullough, G.; Babb, D.

    2014-01-01

    Recent reductions in the summer extent of sea ice have focused the world’s attention on the effects of climate change. Increased CO2-derived global warming is rapidly shrinking the Arctic multi-year ice pack. This shift in ice regimes allows for increasing development opportunities for large oil...... will be a much more complex task than modeling average ice circulation. Given the observed reduction in sea ice extent and thickness this rather counterintuitive situation, associated with a warming climate, poses significant hazards to Arctic marine oil and gas development and marine transportation. Accurate...... forecasting of hazardous ice motion will require improved real-time surface wind and ocean current forecast models capable of ingesting local satellite-derived wind data and/or local, closely-spaced networks of anemometers and improved methods of determining high-frequency components of surface ocean current...

  3. Ecological change drives a decline in mercury concentrations in southern Beaufort Sea polar bears

    Science.gov (United States)

    McKinney, Melissa A.; Atwood, Todd C.; Pedro, Sara; Peacock, Elizabeth

    2017-01-01

    We evaluated total mercury (THg) concentrations and trends in polar bears from the southern Beaufort Sea subpopulation from 2004 to 2011. Hair THg concentrations ranged widely among individuals from 0.6 to 13.3 μg g–1 dry weight (mean: 3.5 ± 0.2 μg g–1). Concentrations differed among sex and age classes: solitary adult females ≈ adult females with cubs ≈ subadults > adult males ≈ yearlings > cubs-of-the-year ≈ 2 year old dependent cubs. No variation was observed between spring and fall samples. For spring-sampled adults, THg concentrations declined by 13% per year, contrasting recent trends observed for other Western Hemispheric Arctic biota. Concentrations also declined by 15% per year considering adult males only, while a slower, nonsignificant decrease of 4.4% per year was found for adult females. Lower THg concentrations were associated with higher body mass index (BMI) and higher proportions of lower trophic position food resources consumed. Because BMI and diet were related, and the relationship to THg was strongest for BMI, trends were re-evaluated adjusting for BMI as the covariate. The adjusted annual decline was not significant. These findings indicate that changes in foraging ecology, not declining environmental concentrations of mercury, are driving short-term declines in THg concentrations in southern Beaufort Sea polar bears.

  4. Organohalogen concentrations in blood and adipose tissue of Southern Beaufort Sea polar bears

    Science.gov (United States)

    Bentzen, T.W.; Muir, D.C.G.; Amstrup, Steven C.; O'Hara, T. M.

    2008-01-01

    We analyzed 151 organohalogen chemicals (OHCs) in whole blood and subcutaneous fat of 57 polar bears sampled along the Alaskan Beaufort Sea coast in spring, 2003. All major organochlorine pesticides, PCBs, PBDEs and their congeners were assessed. Concentrations of most OHCs continue to be lower among Southern Beaufort Sea polar bears than reported for other populations. Additionally, toxaphenes and related compounds were assessed in adipose tissue, and 8 perflourinated compounds (PFCs) were examined in blood. Perfluorooctane sulfonate (PFOS) concentrations exceeded those of any other contaminant measured in blood. ??Chlordane concentrations were higher in females, and both ??PCBs and ??Chlordane concentrations in adipose tissue decreased significantly with age. The rank order of OHC mean concentrations; ??PCB > ??10PCB > PCB153 > ??Chlordane > Oxychlordane > PCB180 > ??HCH > ??-HCH > ??DDT > p,p-DDE > ??PBDE > HCB > Toxaphene was similar for compounds above detection limits in both fat and blood. Although correlation between OHC concentrations in blood and adipose tissue was examined, the predictability of concentrations in one matrix for the other was limited. ?? 2008 Elsevier B.V.

  5. Ecological Change Drives a Decline in Mercury Concentrations in Southern Beaufort Sea Polar Bears.

    Science.gov (United States)

    McKinney, Melissa A; Atwood, Todd C; Pedro, Sara; Peacock, Elizabeth

    2017-07-18

    We evaluated total mercury (THg) concentrations and trends in polar bears from the southern Beaufort Sea subpopulation from 2004 to 2011. Hair THg concentrations ranged widely among individuals from 0.6 to 13.3 μg g -1 dry weight (mean: 3.5 ± 0.2 μg g -1 ). Concentrations differed among sex and age classes: solitary adult females ≈ adult females with cubs ≈ subadults > adult males ≈ yearlings > cubs-of-the-year ≈ 2 year old dependent cubs. No variation was observed between spring and fall samples. For spring-sampled adults, THg concentrations declined by 13% per year, contrasting recent trends observed for other Western Hemispheric Arctic biota. Concentrations also declined by 15% per year considering adult males only, while a slower, nonsignificant decrease of 4.4% per year was found for adult females. Lower THg concentrations were associated with higher body mass index (BMI) and higher proportions of lower trophic position food resources consumed. Because BMI and diet were related, and the relationship to THg was strongest for BMI, trends were re-evaluated adjusting for BMI as the covariate. The adjusted annual decline was not significant. These findings indicate that changes in foraging ecology, not declining environmental concentrations of mercury, are driving short-term declines in THg concentrations in southern Beaufort Sea polar bears.

  6. Subsea Permafrost Mapped Across the U.S. Beaufort Sea Using Multichannel Seismic Data

    Science.gov (United States)

    Brothers, L.; Hart, P. E.; Ruppel, C. D.

    2011-12-01

    Circum-Arctic continental shelves at water depths less than ~100 m were subaerial permafrost prior to the onset of sea-level rise starting in the late Pleistocene. Rapid transgression and the resulting temperature increase at the sediment surface have led to thawing of the inundated permafrost, landward retreat of the leading edge of the permafrost, and dissociation of permafrost-associated gas hydrates. Past numerical modeling has shown that gas hydrate dissociation is particularly pronounced at the permafrost-to-no permafrost transition offshore. On the U.S. Beaufort margin, subsea permafrost has never been systematically mapped, and the best insights about permafrost and associated gas hydrate have been based on a limited number of offshore boreholes and numerical studies, with sometimes contrasting predictions of the permafrost's seaward extent. We bring together 5370 km of multichannel seismic (MCS) data acquired during various proprietary exploration industry and public domain government surveys between 1977 and 1992 to map a velocity anomaly diagnostic of submerged permafrost along 500 km of the US Beaufort coastline. These high-velocity (>~2.8 km/s) refractions (HVR), which are evident in prestack MCS shot records, reveal laterally continuous layers of shallow, ice-bonded, coarse-grained sediments beneath the inner continental shelf. The HVR occur in less than 5% of the tracklines, and calculated HVR depths range from 60 to 350 m below seafloor. The velocity anomaly is not observed seaward of the 20 m isobath, and is only found within 30 km of the current shoreline. These results can be used to: 1) create a map of the minimum distribution of remaining US Beaufort shelf subsea permafrost; 2) reconcile discrepancies between model-predicted and borehole-verified offshore permafrost distribution; and 3) constrain where to expect hydrate dissociation.

  7. Pacific and Atlantic water influence on the Beaufort Sea slope tracked by epifaunal invertebrate biogeography

    Science.gov (United States)

    Bluhm, B.

    2016-02-01

    As an interior Arctic sea with a narrow shelf and a steep slope, the US Beaufort Sea is influenced by complex vertical and horizontal domains of water masses and current regimes. The benthic invertebrates inhabiting that area form communities that reflect the long-term (year to decadal) environmental conditions and waters mass source. During six expeditions over five years, we deployed plumb-staff beam trawls to collect epifauna invertebrates at >150 locations spanning the shelf and slope to 1000 m and across the primary water masses of the region (as defined by T/S). The >250 species sampled in this effort are dominated in species richness by crustaceans and gastropods, and in abundance and biomass by echinoderms and crustaceans, with proportional variations across water depths. We find strong turnover in species and/or community composition with water depth, and moderate shifts along the west-east axis. Depth-related species/community shifts are gradual, but most pronounced around the 20 m isobaths, at the shelf break (between 100 and 200 m) and between 350 and 500 m. Inshore of 20 m, the dynamic environment (ice gouging, variable salinity) results in a species-poor community. At locations deeper than 350 m, communities increasingly include species common in the Atlantic-influenced Arctic and Atlantic-boreal regions, roughly matching the transition from Pacific-origin to Atlantic-origin waters. We conclude that benthic community distribution can delineate boundaries in hydrographic conditions that are characteristic of different water mass types that reside on the shelf and slope of the Beaufort Sea.

  8. Field measurement of local ice pressures on the ARAON in the Beaufort Sea

    Directory of Open Access Journals (Sweden)

    Lee Tak-Kee

    2014-12-01

    Full Text Available This study conducted four field measurements of local ice pressure during the icebreaking voyage of the icebreaking research vessel “ARAON” in the Chukchi and Beaufort seas from July to August of 2010. For measurements, 14 strain gauges, including 8 strain gauge rosettes, were set on the bow of the port side. Influence coefficients were determined using a finite element model of the instrumented area and they were used to convert the measured strains on the hull structure to local ice pressures. The converted maximum pressure was calculated as 2.12 MPa on an area of 0.28 m2. Pressure-area curves were developed from the surveyed pressure data and the results were compared with previously measured data. The study results are expected to provide an understanding of local ice pressures and thus be useful in the structural design of ice class ships.

  9. Field measurement of local ice pressures on the ARAON in the Beaufort Sea

    Science.gov (United States)

    Lee, Tak-Kee; Lee, Jong-Hyun; Kim, Heungsub; Rim, Chae Whan

    2014-12-01

    This study conducted four field measurements of local ice pressure during the icebreaking voyage of the icebreaking research vessel "ARAON" in the Chukchi and Beaufort seas from July to August of 2010. For measurements, 14 strain gauges, including 8 strain gauge rosettes, were set on the bow of the port side. Influence coefficients were determined using a finite element model of the instrumented area and they were used to convert the measured strains on the hull structure to local ice pressures. The converted maximum pressure was calculated as 2.12 MPa on an area of 0.28 m2. Pressure-area curves were developed from the surveyed pressure data and the results were compared with previously measured data. The study results are expected to provide an understanding of local ice pressures and thus be useful in the structural design of ice class ships.

  10. Geotechnical conditions and ice loading for an offshore drilling platform in the Canadian Beaufort Sea

    Energy Technology Data Exchange (ETDEWEB)

    Martens, S.; Eshraghian, A.; Rogers, B. [Klohn Crippen Berger Ltd., Calgary, AB (Canada)

    2009-07-01

    This paper addressed the geotechnical aspects of the deployment of the steel drilling caisson (SDC) at the Paktoa site in the Canadian Beaufort Sea. The SDC is a bottom founded mobile offshore drilling platform that can operate in 8 to 25 m of water in an Arctic environment. It is mated to a submersible barge in order to resist large ice forces on the structure at sites with relatively weak soils, without the need for site preparation. To date, the SDC has been deployed at 8 sites in the Canadian and Alaskan Beaufort Sea. This paper focused on the Paktoa location, where the SDC was deployed 50 km offshore in a water depth of 14 m during the winter of 2005-2006. Geotechnical investigations were conducted from the landfast ice prior to deployment and from the SDC deck. This paper described the soil properties and design loading; design stability; and deformation analysis. The environmental loads considered for the SDC design included ice push, waves and earthquakes. The ice loading was the dominant loading case. The instrumentation installed in the seabed included 2 push-in piezometers and an inclinometer. An ice loading event in February 2006 resulted in considerable displacements in the in-place inclinometer string below the SDC. Several analysis methods were used to estimate the magnitude of the ice load during this event in order to better understand the magnitude of ice loading for future Arctic deployments of gravity based drilling platforms. It was concluded that further deployments should have a minimum of 2 and preferably 4 in-place inclinometer strings to measure real-time deformation of the seabed to enable measurement of rotation of the structure that may occur due to asymmetrical ice loading. 10 refs., 2 tabs., 15 figs.

  11. Age and sex composition of seals killed by polar bears in the eastern Beaufort Sea.

    Directory of Open Access Journals (Sweden)

    Nicholas W Pilfold

    Full Text Available BACKGROUND: Polar bears (Ursus maritimus of the Beaufort Sea enter hyperphagia in spring and gain fat reserves to survive periods of low prey availability. We collected information on seals killed by polar bears (n=650 and hunting attempts on ringed seal (Pusa hispida lairs (n=1396 observed from a helicopter during polar bear mark-recapture studies in the eastern Beaufort Sea in spring in 1985-2011. We investigated how temporal shifts in ringed seal reproduction affect kill composition and the intraspecific vulnerabilities of ringed seals to polar bear predation. PRINCIPAL FINDINGS: Polar bears primarily preyed on ringed seals (90.2% while bearded seals (Erignathus barbatus only comprised 9.8% of the kills, but 33% of the biomass. Adults comprised 43.6% (150/344 of the ringed seals killed, while their pups comprised 38.4% (132/344. Juvenile ringed seals were killed at the lowest proportion, comprising 18.0% (62/344 of the ringed seal kills. The proportion of ringed seal pups was highest between 2007-2011, in association with high ringed seal productivity. Half of the adult ringed seal kills were ≥ 21 years (60/121, and kill rates of adults increased following the peak of parturition. Determination of sex from DNA revealed that polar bears killed adult male and adult female ringed seals equally (0.50, n=78. The number of hunting attempts at ringed seal subnivean lair sites was positively correlated with the number of pup kills (r(2 =0.30, P=0.04, but was not correlated with the number of adult kills (P=0.37. CONCLUSIONS/SIGNIFICANCE: Results are consistent with decadal trends in ringed seal productivity, with low numbers of pups killed by polar bears in spring in years of low pup productivity, and conversely when pup productivity was high. Vulnerability of adult ringed seals to predation increased in relation to reproductive activities and age, but not gender.

  12. The first hop: Use of Beaufort Sea deltas by hatch-year semipalmated sandpipers

    Science.gov (United States)

    Churchwell, Roy T.; Kendall, Steve J.; Brown, Stephen C.; Blanchard, Arny L.; Hollmen, Tuula E.; Powell, Abby

    2018-01-01

    River deltas along Alaska’s Beaufort Sea coast are used by hatch-year semipalmated sandpipers (Calidris pusilla) after leaving their terrestrial natal sites, but the drivers of their use of these stopover sites on the first “hop” of fall migration are unknown. We quantified sandpiper temporal distribution and abundance as related to food resources at three river deltas during the beginning of their fall migration (post-breeding period) to compare the habitat quality among these deltas. We conducted population counts, sampled invertebrates, and captured birds to collect blood samples from individuals for triglyceride and stable isotope analyses to determine fattening rates and diet. Patterns of sandpiper and invertebrate abundance were complex and varied among deltas and within seasons. River deltas were used by sandpipers from late July to late August, and peak sandpiper counts ranged from 1000 to 4000 individuals, of which 98% were hatch-year semipalmated sandpipers. Isotopic signatures from blood plasma samples indicated that birds switched from a diet of upland tundra to delta invertebrate taxa as the migration season progressed, suggesting a dependence on delta invertebrates. Despite differences in diet among deltas, we found no differences in fattening rates of juvenile sandpipers as indicated by triglyceride levels. The number of sandpipers was positively associated with abundance of Amphipoda and Oligochaeta at the Jago and Okpilak-Hulahula deltas; an isotopic mixing model indicated that sandpipers consumed Amphipoda and Oligochaeta at Jago, mostly Chironomidae at Okpilak-Hulahula and Spionidae at Canning. Regardless of the difference in sandpiper diets at the Beaufort Sea deltas, their similar fattening rates throughout the season indicate that all of these stopover sites provide a critical food resource for hatch-year sandpipers beginning their first migration.

  13. Age and sex composition of seals killed by polar bears in the eastern Beaufort Sea.

    Science.gov (United States)

    Pilfold, Nicholas W; Derocher, Andrew E; Stirling, Ian; Richardson, Evan; Andriashek, Dennis

    2012-01-01

    Polar bears (Ursus maritimus) of the Beaufort Sea enter hyperphagia in spring and gain fat reserves to survive periods of low prey availability. We collected information on seals killed by polar bears (n=650) and hunting attempts on ringed seal (Pusa hispida) lairs (n=1396) observed from a helicopter during polar bear mark-recapture studies in the eastern Beaufort Sea in spring in 1985-2011. We investigated how temporal shifts in ringed seal reproduction affect kill composition and the intraspecific vulnerabilities of ringed seals to polar bear predation. Polar bears primarily preyed on ringed seals (90.2%) while bearded seals (Erignathus barbatus) only comprised 9.8% of the kills, but 33% of the biomass. Adults comprised 43.6% (150/344) of the ringed seals killed, while their pups comprised 38.4% (132/344). Juvenile ringed seals were killed at the lowest proportion, comprising 18.0% (62/344) of the ringed seal kills. The proportion of ringed seal pups was highest between 2007-2011, in association with high ringed seal productivity. Half of the adult ringed seal kills were ≥ 21 years (60/121), and kill rates of adults increased following the peak of parturition. Determination of sex from DNA revealed that polar bears killed adult male and adult female ringed seals equally (0.50, n=78). The number of hunting attempts at ringed seal subnivean lair sites was positively correlated with the number of pup kills (r(2) =0.30, P=0.04), but was not correlated with the number of adult kills (P=0.37). Results are consistent with decadal trends in ringed seal productivity, with low numbers of pups killed by polar bears in spring in years of low pup productivity, and conversely when pup productivity was high. Vulnerability of adult ringed seals to predation increased in relation to reproductive activities and age, but not gender.

  14. SBI AWS02-I Bottle and Nutrient Data collected from the Polar Star in the Beaufort and Chukchi Seas (NODC Accession 0001288)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The field phase of the Shelf-Basin Interactions Experiment (SBI) began in 2002 with a series of three cruises to the Chukchi and Beaufort Seas. SBI is a...

  15. Polar bear population status in the northern Beaufort Sea, Canada, 1971-2006.

    Science.gov (United States)

    Stirling, Ian; McDonald, Trent L; Richardson, E S; Regehr, Eric V; Amstrup, Steven C

    2011-04-01

    Polar bears (Ursus maritimus) of the northern Beaufort Sea (NB) population occur on the perimeter of the polar basin adjacent to the northwestern islands of the Canadian Arctic Archipelago. Sea ice converges on the islands through most of the year. We used open-population capture-recapture models to estimate population size and vital rates of polar bears between 1971 and 2006 to: (1) assess relationships between survival, sex and age, and time period; (2) evaluate the long-term importance of sea ice quality and availability in relation to climate warming; and (3) note future management and conservation concerns. The highest-ranking models suggested that survival of polar bears varied by age class and with changes in the sea ice habitat. Model-averaged estimates of survival (which include harvest mortality) for senescent adults ranged from 0.37 to 0.62, from 0.22 to 0.68 for cubs of the year (COY) and yearlings, and from 0.77 to 0.92 for 2-4 year-olds and adults. Horvtiz-Thompson (HT) estimates of population size were not significantly different among the decades of our study. The population size estimated for the 2000s was 980 +/- 155 (mean and 95% CI). These estimates apply primarily to that segment of the NB population residing west and south of Banks Island. The NB polar bear population appears to have been stable or possibly increasing slightly during the period of our study. This suggests that ice conditions have remained suitable and similar for feeding in summer and fall during most years and that the traditional and legal Inuvialuit harvest has not exceeded sustainable levels. However, the amount of ice remaining in the study area at the end of summer, and the proportion that continues to lie over the biologically productive continental shelf (polar bear population in the northern Beaufort Sea will eventually decline. Management and conservation practices for polar bears in relation to both aboriginal harvesting and offshore industrial activity will need to

  16. The 2015 Spring Freshet and Its Effects on the Alaskan Beaufort Sea

    Science.gov (United States)

    Kasper, J.; Trefry, J. H.; Fox, A. L.; Savoie, M.; Fox, S. L.; Lawley, G.; Trocine, R. P.; Shipton, P.

    2016-02-01

    In 2015, a unique set of measurements were collected from the landfast ice of the Alaskan Beaufort Sea, as the buoyant plume resulting from the spring freshet of the largest Arctic Alaska river, the Colville, spread beneath the sea ice covering Harrison Bay. Velocities of both the plume and the ambient shelf water beneath the plume were measured as well as salinity and temperature, particle size and concentration. A suite of geochemical measurements including dissolved oxygen, pH, total suspended solids, dissolved and particulate metals N, P, C and δ18O were made at the same time. In addition, the Colville as well as the nearby Sagavanirktok and Kuparak Rivers were sampled for many of these same parameters. This comprehensive set of measurements allows us to describe in detail the dynamics of the spring 2015 under ice freshet. The 2015 freshet on the North Slope of Alaska was marked by the rapid onset of melt simultaneously across the entire slope resulting in melt water rapidly spreading both over and under the sea ice north from the coast. Consistent with simple numerical models, the thickness of the buoyant under ice plume increased rapidly with time as well.

  17. Site-Specific Bluff Recession Rates Measured on the Alaskan Beaufort Sea Coast

    Science.gov (United States)

    Richmond, B.; Gadd, P.; Crowell, W.

    2017-12-01

    OverviewThe effects of climate change are being studied globally with coastal erosion in Arctic regions of particular concern. In support of Hilcorp Alaska's Northstar Development, short- and long-term bluff recession rates have been documented at a pipeline shore crossing located in Gwydyr Bay on the Alaskan Beaufort Sea coast. These data are presented, along with the predominant forcing mechanisms, and compared to local and regional recession rates recently published by the U.S. Geological Survey (USGS). Arctic Bluff RecessionCoastal retreat along the northern coast of Alaska occurs at two different rates: infrequent, but rapid erosion induced by strong westerly storms, and seasonal retreat related to thawing and sediment removal under more moderate wave conditions. Variability in the rate of bluff retreat is related to a number of factors, including bluff composition (ice content and sediment type), existence of a fronting beach, and wave exposure. Measured Bluff Recession at the Northstar Pipeline Shore CrossingThe location of the Northstar Development pipeline shore crossing was chosen based on analysis of historical aerial photos acquired between 1949 and 1996. Over this 47-year period, the average annualized rate of bluff retreat in the study area ranged from 1.6 to 3.0 ft/yr. Beginning in 1996, ground-based shoreline monitoring surveys have been conducted along the bluff and ten shore-perpendicular transects at the site. The rates of bluff retreat derived from the survey data have been modest, ranging from no change to 5.8 ft/yr. The monitoring surveys indicate that waves and currents erode the bluffs by direct impact only during infrequent, but strong westerly storms that promote a short-term rise in sea level (storm surge). The more prevalent easterly storms can cause set-down, or reduction in the sea level which limits direct wave impact on the bluff, thereby decreasing the potential for wave induced erosion. Comparative StudiesRecent studies conducted

  18. Trophic transfer of persistent organochlorine contaminants (OCs) within an Arctic marine food web from the southern Beaufort-Chukchi Seas

    International Nuclear Information System (INIS)

    Hoekstra, P.F.; O'Hara, T.M.; Fisk, A.T.; Borgaa, K.; Solomon, K.R.; Muir, D.C.G.

    2003-01-01

    The trophic status and biomagnification of persistent OCs within the near-shore Beaufort-Chukchi Seas food web from Barrow, AK is discussed. - Stable isotope values (δ 13 C, δ 15 N) and concentrations of persistent organochlorine contaminants (OCs) were determined to evaluate the near-shore marine trophic status of biota and biomagnification of OCs from the southern Beaufort-Chukchi Seas (1999-2000) near Barrow, AK. The biota examined included zooplankton (Calanus spp.), fish species such as arctic cod (Boreogadus saida), arctic char (Salvelinus alpinus), pink salmon (Oncorhynchus gorbuscha), and fourhorn sculpin (Myoxocephalus quadricornis), along with marine mammals, including bowhead whales (Balaena mysticetus), beluga whales (Delphinapterus leucas), ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus). The isotopically derived trophic position of biota from the Beaufort-Chukchi Seas marine food web, avian fauna excluded, is similar to other coastal food webs in the Arctic. Concentrations of OCs in marine mammals were significantly greater than in fish and corresponded with determined trophic level. In general, OCs with the greatest food web magnification factors (FWMFs) were those either formed due to biotransformation (e.g. p,p'-DDE, oxychlordane) or considered recalcitrant (e.g. β-HCH, 2,4,5-Cl substituted PCBs) in most biota, whereas concentrations of OCs that are considered to be readily eliminated (e.g. γ-HCH) did not correlate with trophic level. Differences in physical-chemical properties of OCs, feeding strategy and possible biotransformation were reflected in the variable biomagnification between fish and marine mammals. The FWMFs in the Beaufort-Chukchi Seas region were consistent with reported values in the Canadian Arctic and temperate food webs, but were statistically different than FWMFs from the Barents and White Seas, indicating that the spatial variability of OC contamination in top-level marine Arctic predators is

  19. Aerial Surveys of the Beaufort Sea Seasonal Ice Zone in 2012-2014

    Science.gov (United States)

    Dewey, S.; Morison, J.; Andersen, R.; Zhang, J.

    2014-12-01

    Seasonal Ice Zone Reconnaissance Surveys (SIZRS) of the Beaufort Sea aboard U.S. Coast Guard Arctic Domain Awareness flights were made monthly from May 2012 to October 2012, June 2013 to August 2013, and June 2014 to October 2014. In 2012 sea ice extent reached a record minimum and the SIZRS sampling ranged from complete ice cover to open water; in addition to its large spatial coverage, the SIZRS program extends temporal coverage of the seasonal ice zone (SIZ) beyond the traditional season for ship-based observations, and is a good set of measurements for model validation and climatological comparison. The SIZ, where ice melts and reforms annually, encompasses the marginal ice zone (MIZ). Thus SIZRS tracks interannual MIZ conditions, providing a regional context for smaller-scale MIZ processes. Observations with Air eXpendable CTDs (AXCTDs) reveal two near-surface warm layers: a locally-formed surface seasonal mixed layer and a layer of Pacific origin at 50-60m. Temperatures in the latter differ from the freezing point by up to 2°C more than climatologies. To distinguish vertical processes of mixed layer formation from Pacific advection, vertical heat and salt fluxes are quantified using a 1-D Price-Weller-Pinkel (PWP) model adapted for ice-covered seas. This PWP simulates mixing processes in the top 100m of the ocean. Surface forcing fluxes are taken from the Marginal Ice Zone Modeling and Assimilation System MIZMAS. Comparison of SIZRS observations with PWP output shows that the ocean behaves one-dimensionally above the Pacific layer of the Beaufort Gyre. Despite agreement with the MIZMAS-forced PWP, SIZRS observations remain fresher to 100m than do outputs from MIZMAS and ECCO.2. The shapes of seasonal cycles in SIZRS salinity and temperature agree with MIZMAS and ECCO.2 model outputs despite differences in the values of each. However, the seasonal change of surface albedo is not high enough resolution to accurately drive the PWP. Use of ice albedo

  20. The Floe Size Distribution in the Marginal Ice Zone of the Beaufort and Chukchi Seas

    Science.gov (United States)

    Schweiger, A. J. B.; Stern, H. L., III; Stark, M.; Zhang, J.; Hwang, P. B.; Steele, M.

    2016-02-01

    In order to support the calibration and validation of our high-resolution coupled sea ice/ocean modeling and assimilation system, which now includes a floe size distribution (FSD), we have analyzed the FSD in 256 MODIS satellite images from 2013 and 2014 in the Marginal Ice Zone (MIZ) of the Beaufort and Chukchi seas. Proper characterization of the FSD is important for modeling the MIZ. We find that the FSD (the number of floes in different size categories) obeys a power-law distribution with an exponent that varies systematically over the course of spring, summer, and fall. The exponent (or slope in log-log space) is relatively shallow in spring but becomes steeper in summer, reflecting the fact that floes break up, resulting in fewer large floes relative to the number of small floes. In late summer the slope becomes shallower again, since small floes melt more quickly than large floes. The spatial resolution of MODIS limits our analysis to floes larger than about 1 km in diameter. To investigate smaller scales, we calculated the FSD in satellite images from radar (SAR, 50-meter resolution) and optical (MEDEA, 1-meter resolution) sensors that overlap in space and time with MODIS images, to see whether the power-law FSD in the MODIS images extends to smaller scales. We present the results of those calculations, as well as comparisons between the modeled and observed FSD.

  1. The Floe Size Distribution in the Marginal Ice Zone of the Beaufort and Chukchi Seas

    Science.gov (United States)

    Schweiger, A. J. B.; Stern, H. L., III; Stark, M.; Zhang, J.; Steele, M.; Hwang, P. B.

    2014-12-01

    Several key processes in the Marginal Ice Zone (MIZ) of the Arctic Ocean are related to the size of the ice floes, whose diameters range from meters to tens of kilometers. The floe size distribution (FSD) influences the mechanical properties of the ice cover, air-sea momentum and heat transfer, lateral melting, and light penetration. However, no existing sea-ice/ocean models currently simulate the FSD in the MIZ. Model development depends on observations of the FSD for parameterization, calibration, and validation. To support the development and implementation of the FSD in the Marginal Ice Zone Modeling and Assimilation System (MIZMAS), we have analyzed the FSD in the Beaufort and Chukchi seas using multiple sources of satellite imagery: NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra and Aqua satellites (250 m pixel size), the USGS Landsat 8 satellite (80 m pixel size), the Canadian Space Agency's synthetic aperture radar (SAR) on RADARSAT (50 meter pixel size), and declassified National Technical Means imagery from the Global Fiducials Library (GFL) of the USGS (1 m pixel size). The procedure for identifying ice floes in the imagery begins with manually delineating cloud-free regions (if necessary). A threshold is then chosen to separate ice from water. Morphological operations and other semi-automated techniques are used to identify individual floes, whose properties are then easily calculated. We use the mean caliper diameter as the measure of floe size. The FSD is adequately described by a power-law in which the exponent characterizes the relative number of large and small floes. Changes in the exponent over time and space reflect changes in physical processes in the MIZ, such as sea-ice deformation, fracturing, and melting. We report results of FSD analysis for the spring and summer of 2013 and 2014, and show how the FSD will be incorporated into the MIZMAS model.

  2. Modeling the rate and style of Arctic coastal retreat along the Beaufort Sea, Alaska

    Science.gov (United States)

    Barnhart, K. R.; Anderson, R. S.; Overeem, I.; Wobus, C. W.; Clow, G. D.; Urban, F. E.; Stanton, T. P.

    2010-12-01

    In Arctic landscapes, modern surface warming has significantly altered geomorphic process rates. Along the Beaufort Sea coastline bounding Alaska’s North Slope, the mean annual coastal erosion rate has doubled from ~7 m/yr for 1955-1979 to ~14 m/yr for 2002-2007 (Mars and Houseknecht, 2007). Locally the erosion rate can reach 30 m/yr, with short-term rates that are far greater than this. A robust understanding of the processes that govern the rate of coastal erosion is required in order to predict the response of the coast and its adjacent landscape to a rapidly changing climate, with implications for sediment and carbon fluxes, oilfield infrastructure, and animal habitat. Constrained by time-lapse imagery, and by measurements of both the oceanic and atmospheric conditions, we have developed a numerical model to capture the evolution of the permafrost bluffs on the North Slope. During the sea ice-free season, relatively warm waters melt a notch into the ice-rich silt that comprises the 4-m tall bluffs. The bluffs ultimately fail by toppling of polygonal blocks bounded by mechanically weak ice-wedges that are spaced roughly 10-20 m apart. The toppled blocks then temporarily armor the coast against further attack. The annual retreat rate is controlled by the length of the sea ice-free season, water and air temperatures, and the wave history. Honoring the high ice content of the bluff materials, we employ a positive degree day algorithm to govern subaerial melt, and an iceberg melting algorithm to determine rate of notch incision. In the iceberg melting algorithm, the local instantaneous melt rate goes as the product of the temperature difference between seawater and bluff material, the sea state, captured by the ratio of wave height to wave period, and the ratio of ice surface roughness to wave height to the 0.2 power (Kubat et al., 2007). The calculated instantaneous melt rate is adjusted to account for the ambient temperature of the permafrost and the presence of

  3. Notice of availability, final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project

    International Nuclear Information System (INIS)

    1999-01-01

    BP Exploration (Alaska) Inc. (BPXA) is proposing to develop the Northstar Unit, located approximately 6 miles offshore of Point Storkensen in the Alaskan Beaufort Sea. BPXA's proposed action is a self-contained development/production facility located on a reconstructed gravel island in 39 feet of water. Also proposed is construction of two buried subsea pipelines between the island and shoreline to transport oil and gas. The pipelines would connect with onshore facilities and the Trans Alaska Pipeline System (TAPS). In response to BPXA's submittal of a permit application under Section 10 of the Rivers and Harbors Act, Section 404 of the Clean Water Act, and Section 103 of the Marine Protection Research and Sanctuaries Act, the US Army Corps of engineers, Alaska District (Corps) determined that issuance of a permit for BPXA's proposed project constituted a major federal action that may significantly affect the quality of the human environment pursuant to the National Environmental Policy Act (NEPA). In addition, the US Environmental Protection Agency (EPA), determined under provisions of the Clean Water Act and 40 CFR Part 6 Subpart F that permitting by the EPA for BPXA's proposed project also constituted a major federal action that my significantly affect the quality of the human environment. As a result, preparation of an Environmental Impact Statement (EIS) under NEPA was undertaken to identify and evaluate a range of reasonable alternatives and evaluate the potential effects the alternates, including BPXA's proposed project, may have on the human environment

  4. Limited contribution of ancient methane to surface waters of the U.S. Beaufort Sea shelf

    Science.gov (United States)

    Sparrow, Katy J.; Kessler, John D.; Southon, John R.; Garcia-Tigreros, Fenix; Schreiner, Kathryn M.; Ruppel, Carolyn D.; Miller, John B.; Lehman, Scott J.; Xu, Xiaomei

    2018-01-01

    In response to warming climate, methane can be released to Arctic Ocean sediment and waters from thawing subsea permafrost and decomposing methane hydrates. However, it is unknown whether methane derived from this sediment storehouse of frozen ancient carbon reaches the atmosphere. We quantified the fraction of methane derived from ancient sources in shelf waters of the U.S. Beaufort Sea, a region that has both permafrost and methane hydrates and is experiencing significant warming. Although the radiocarbon-methane analyses indicate that ancient carbon is being mobilized and emitted as methane into shelf bottom waters, surprisingly, we find that methane in surface waters is principally derived from modern-aged carbon. We report that at and beyond approximately the 30-m isobath, ancient sources that dominate in deep waters contribute, at most, 10 ± 3% of the surface water methane. These results suggest that even if there is a heightened liberation of ancient carbon–sourced methane as climate change proceeds, oceanic oxidation and dispersion processes can strongly limit its emission to the atmosphere.

  5. Aerial surveys of endangered whales in the Beaufort Sea, Fall 1989. Final report

    International Nuclear Information System (INIS)

    Treacy, S.D.

    1990-11-01

    The OCSLA Amendments of 1978 (43 U.S.C. 1802) established a policy for the management of oil and natural gas in the OCS and for protection of the marine and coastal environments. The amended OCSLA authorizes the Secretary of the Interior to conduct studies in areas or regions of sales to ascertain the environmental impacts on the marine and coastal environments of the outer Continental Shelf and the coastal areas which may be affected by oil and gas development (43 U.S.C. 1346). The report describes field activities and data analyses for aerial surveys of bowhead whales conducted between 1 September 1989 and 20 October 1989 in the Beaufort Sea, primarily between 140 W. and 154 W. longitudes south of 72 N. latitude. Ice cover during September and October 1989 was exceptionally light. A total of 215 bowhead whales, 104 belukha whales, 9 bearded seals, 84 ringed seals, and 32 unidentified pinnipeds were observed in 1989 during 98.70 hours of survey effort that included 38.10 hours on randomized transects. The last sighting of a bowhead whale made during the survey occurred in open water on 19 October 1989. No whales were sighted during a subsequent flight on 20 October 1989. Estimated median and mean water depths were shallower than for previous surveys (1982-1989). This is consistent with a trend for whales to be located in shallower water during years of generally light ice cover

  6. The Under-ice Soundscape of the Southern Beaufort Sea Observed During ICEX-16

    Science.gov (United States)

    Joseph, J.; Margolina, T.; Reeder, D. B. B.; Doyle, L. J.

    2016-12-01

    Located approximately 175 nautical miles north of Prudhoe Bay Alaska, Ice Camp SARGO was the remote hub of operations for the multi-national naval exercise ICEX-16 held in March 2016. Continuous acoustic recordings of the under-ice soundscape were collected at various depths over a three day period in the vicinity of the ice camp as it drifted westward across the Beaufort Sea. Significant changes in environmental conditions resulted in irregular ice motion during the period of observation inducing notable ice cracking and ridging events near the camp. Ice movement slowed from about 0.5 knots early in the test to virtually coming to a halt near the end of the recording period. Sounds from naturally occurring and anthropogenic sources in the 10-Hz to 10-kHz band detected in the recordings were analyzed in connection to the origins of the sound and correlated to varying environment conditions including wind speed and ice motion. Results show a wide variety of persistent and transient sources contribute to the total soundscape of this remote location.

  7. Arctic data compilation and appraisal. Vol. 10, Beaufort Sea: Biological oceanography - whales 1848 to 1983

    Energy Technology Data Exchange (ETDEWEB)

    Norton, P.; Smiley, B.D.; de March, L.

    1987-01-01

    This data report is an inventory of measurements and observations of white whales, bowhead whales, gray whales, harbour porpoises, narwhal, and killer whales in the Beaufort Sea and Amundsen Gulf. Measurements most commonly reported concern numbers, identification, movements, morphometrics, age behaviour, food, and reproduction. Organization within this inventory is by data set (measurements and observations made by one group of people, for a particular purpose, generally within one year). In all, 143 data sets were inventoried for the 1848 to 1983 period. Times and locations of sampling efforts are listed in tables and also are shown on computer-drawn maps. Sampling methodology and intensity, whale measurements and observations obtained by species, and concurrent bio logical, physical, and chemical measurements are described in the tables. A five-level rating system, based on sampling methodolgy, is outlined and has been applied to each measurement in each data set as a rough indication of the data's reliability. Data sets are indexed according to geographic coverage, study methods, species, measurements and observations made by category, and published references. The form, location, and availability of original data is given if know. 74 refs 115 figs 3 tabs

  8. Polar bear population status in the northern Beaufort Sea, Canada, 1971-2006

    Science.gov (United States)

    Stirling, I.; McDonald, T.L.; Richardson, E.S.; Regehr, E.V.; Amstrup, Steven C.

    2011-01-01

    Polar bears (Ursus maritimus) of the northern Beaufort Sea (NB) population occur on the perimeter of the polar basin adjacent to the northwestern islands of the Canadian Arctic Archipelago. Sea ice converges on the islands through most of the year. We used open-population capture–recapture models to estimate population size and vital rates of polar bears between 1971 and 2006 to: (1) assess relationships between survival, sex and age, and time period; (2) evaluate the long-term importance of sea ice quality and availability in relation to climate warming; and (3) note future management and conservation concerns. The highest-ranking models suggested that survival of polar bears varied by age class and with changes in the sea ice habitat. Model-averaged estimates of survival (which include harvest mortality) for senescent adults ranged from 0.37 to 0.62, from 0.22 to 0.68 for cubs of the year (COY) and yearlings, and from 0.77 to 0.92 for 2–4 year-olds and adults. Horvtiz-Thompson (HT) estimates of population size were not significantly different among the decades of our study. The population size estimated for the 2000s was 980 ± 155 (mean and 95% CI). These estimates apply primarily to that segment of the NB population residing west and south of Banks Island. The NB polar bear population appears to have been stable or possibly increasing slightly during the period of our study. This suggests that ice conditions have remained suitable and similar for feeding in summer and fall during most years and that the traditional and legal Inuvialuit harvest has not exceeded sustainable levels. However, the amount of ice remaining in the study area at the end of summer, and the proportion that continues to lie over the biologically productive continental shelf (Sea will eventually decline. Management and conservation practices for polar bears in relation to both aboriginal harvesting and offshore industrial activity will need to adapt.

  9. Degradation state of organic matter in surface sediments from the Southern Beaufort Sea: a lipid approach

    Directory of Open Access Journals (Sweden)

    J.-F. Rontani

    2012-09-01

    Full Text Available For the next decades significant climatic changes should occur in the Arctic zone. The expected destabilisation of permafrost and its consequences for hydrology and plant cover should increase the input of terrigenous carbon to coastal seas. Consequently, the relative importance of the fluxes of terrestrial and marine organic carbon to the seafloor will likely change, strongly impacting the preservation of organic carbon in Arctic marine sediments. Here, we investigated the lipid content of surface sediments collected on the Mackenzie basin in the Beaufort Sea. Particular attention was given to biotic and abiotic degradation products of sterols and monounsaturated fatty acids. By using sitosterol and campesterol degradation products as tracers of the degradation of terrestrial higher plant inputs and brassicasterol degradation products as tracers of degradation of phytoplanktonic organisms, it could be observed that autoxidation, photooxidation and biodegradation processes act much more intensively on higher plant debris than on phytoplanktonic organisms. Examination of oxidation products of monounsaturated fatty acids showed that photo- and autoxidation processes act more intensively on bacteria than on phytodetritus. Enhanced damages induced by singlet oxygen (transferred from senescent phytoplanktonic cells in bacteria were attributed to the lack of an adapted antioxidant system in these microorganisms. The strong oxidative stress observed in the sampled sediments resulted in the production of significant amounts of epoxy acids and unusually high proportions of monounsaturated fatty acids with a trans double bond. The formation of epoxy acids was attributed to peroxygenases (enzymes playing a protective role against the deleterious effects of fatty acid hydroperoxides in vivo, while cis/trans isomerisation was probably induced by thiyl radicals produced during the reaction of thiols with hydroperoxides. Our results confirm the

  10. Degradation state of organic matter in surface sediments from the Southern Beaufort Sea: a lipid approach

    Science.gov (United States)

    Rontani, J.-F.; Charriere, B.; Petit, M.; Vaultier, F.; Heipieper, H. J.; Link, H.; Chaillou, G.; Sempéré, R.

    2012-09-01

    For the next decades significant climatic changes should occur in the Arctic zone. The expected destabilisation of permafrost and its consequences for hydrology and plant cover should increase the input of terrigenous carbon to coastal seas. Consequently, the relative importance of the fluxes of terrestrial and marine organic carbon to the seafloor will likely change, strongly impacting the preservation of organic carbon in Arctic marine sediments. Here, we investigated the lipid content of surface sediments collected on the Mackenzie basin in the Beaufort Sea. Particular attention was given to biotic and abiotic degradation products of sterols and monounsaturated fatty acids. By using sitosterol and campesterol degradation products as tracers of the degradation of terrestrial higher plant inputs and brassicasterol degradation products as tracers of degradation of phytoplanktonic organisms, it could be observed that autoxidation, photooxidation and biodegradation processes act much more intensively on higher plant debris than on phytoplanktonic organisms. Examination of oxidation products of monounsaturated fatty acids showed that photo- and autoxidation processes act more intensively on bacteria than on phytodetritus. Enhanced damages induced by singlet oxygen (transferred from senescent phytoplanktonic cells) in bacteria were attributed to the lack of an adapted antioxidant system in these microorganisms. The strong oxidative stress observed in the sampled sediments resulted in the production of significant amounts of epoxy acids and unusually high proportions of monounsaturated fatty acids with a trans double bond. The formation of epoxy acids was attributed to peroxygenases (enzymes playing a protective role against the deleterious effects of fatty acid hydroperoxides in vivo), while cis/trans isomerisation was probably induced by thiyl radicals produced during the reaction of thiols with hydroperoxides. Our results confirm the important role played by abiotic

  11. Stopover ecology of Semipalmated Sandpipers (Calidris pusilla) at coastal deltas of the Beaufort Sea, Alaska

    Science.gov (United States)

    Churchwell, Roy T.

    Avian migration is one of the wonders of the natural world. Stored fats are the main source of nutrients and fuel for avian migration and it is assumed the fat deposition at stopover sites is a critical component of a successful migration. Stopover sites are crucial in the successful migration of many birds, but particularly for arctic-breeding shorebirds that migrate long distances from breeding to wintering grounds. Despite the importance of stopover sites, it is often difficult to determine the importance of these sites to migrating shorebirds. I investigated three aspects of stopover ecology of Semipalmated Sandpipers (Calidris pusilla) foraging at coastal deltas on the Beaufort Sea coast, Alaska. First, I quantified the spatial and temporal distribution and abundance of the benthic macroinvertebrate community living within the mudflats. I found that there were two ecological groups of macroinvertebrates using river deltas, one originated in terrestrial freshwater habitats and most importantly could withstand freezing in delta sediments over the winter, and the other originated from the marine environment, could not withstand freezing and had to migrate to intertidal habitats each summer from deeper water areas that did not freeze over the winter. Stable isotope analysis allowed me to describe the origin of carbon consumed by invertebrates in intertidal habitats. I predicted freshwater invertebrates would consume terrestrial carbon, and marine invertebrates would consume marine carbon, but I found that both groups utilized the same carbon, which was a mixture of terrestrial and marine sources. My second research question determined the importance of delta foraging habitat for fall migrating Semipalmated Sandpipers. I mapped the temporal distribution and abundance of birds and quantified this relationship to invertebrate distribution and abundance. I researched fattening rates of shorebirds by measuring triglycerides in the blood of shorebirds I captured. I

  12. Photoproduction of ammonium in the southeastern Beaufort Sea and its biogeochemical implications

    Directory of Open Access Journals (Sweden)

    H. Xie

    2012-08-01

    Full Text Available Photochemistry of dissolved organic matter (DOM plays an important role in marine biogeochemical cycles, including the regeneration of inorganic nutrients. DOM photochemistry affects nitrogen cycling by converting bio-refractory dissolved organic nitrogen to labile inorganic nitrogen, mainly ammonium (NH4+. During the August 2009 Mackenzie Light and Carbon (MALINA Program, the absorbed photon-based efficiency spectra of NH4+ photoproduction (i.e. photoammonification were determined using water samples from the SE Beaufort Sea, including the Mackenzie River estuary, shelf, and Canada Basin. The photoammonification efficiency decreased with increasing wavelength across the ultraviolet and visible regimes and was higher in offshore waters than in shelf and estuarine waters. The efficiency was positively correlated with the molar nitrogen:carbon ratio of DOM and negatively correlated with the absorption coefficient of chromophoric DOM (CDOM. Combined with collateral measurements of CO2 and CO photoproduction, this study revealed a stoichiometry of DOM photochemistry with a CO2 : CO : NH4+ molar ratio of 165 : 11 : 1 in the estuary, 60 : 3 : 1 on the shelf, and 18 : 2 : 1 in the Canada Basin. The NH4+ efficiency spectra, along with solar photon fluxes, CDOM absorption coefficients and sea ice concentrations, were used to model the monthly surface and depth-integrated photoammonification rates in 2009. The summertime (June–August rates at the surface reached 6.6 nmol l−1 d−1 on the Mackenzie Shelf and 3.7 nmol l−1 d−1 further offshore; the depth-integrated rates were correspondingly 8.8 μmol m−2 d−1 and 11.3 μmol m−2 d−1. The offshore depth-integrated rate in August (8.0 μmol m−2 d−1 was comparable to the

  13. Inorganic carbon fluxes on the Mackenzie Shelf of the Beaufort Sea

    Science.gov (United States)

    Mol, Jacoba; Thomas, Helmuth; Myers, Paul G.; Hu, Xianmin; Mucci, Alfonso

    2018-02-01

    The Mackenzie Shelf in the southeastern Beaufort Sea is a region that has experienced large changes in the past several decades as warming, sea-ice loss, and increased river discharge have altered carbon cycling. Upwelling and downwelling events are common on the shelf, caused by strong, fluctuating along-shore winds, resulting in cross-shelf Ekman transport, and an alternating estuarine and anti-estuarine circulation. Downwelling carries dissolved inorganic carbon (DIC) and other remineralization products off the shelf and into the deep basin for possible long-term storage in the world's oceans. Upwelling carries DIC and nutrient-rich waters from the Pacific-origin upper halocline layer (UHL) onto the shelf. Profiles of DIC and total alkalinity (TA) taken in August and September of 2014 are used to investigate the cycling of carbon on the Mackenzie Shelf. The along-shore transport of water and the cross-shelf transport of DIC are quantified using velocity field output from a simulation of the Arctic and Northern Hemisphere Atlantic (ANHA4) configuration of the Nucleus of European Modelling of the Ocean (NEMO) framework. A strong upwelling event prior to sampling on the Mackenzie Shelf took place, bringing CO2-rich (elevated pCO2) water from the UHL onto the shelf bottom. The maximum on-shelf DIC flux was estimated at 16.9×103 mol C d-1 m-2 during the event. The maximum on-shelf transport of DIC through the upwelling event was found to be 65±15×10-3 Tg C d-1. TA and the oxygen isotope ratio of water (δ18O-H2O) are used to examine water-mass distributions in the study area and to investigate the influence of Pacific Water, Mackenzie River freshwater, and sea-ice melt on carbon dynamics and air-sea fluxes of carbon dioxide (CO2) in the surface mixed layer. Understanding carbon transfer in this seasonally dynamic environment is key to quantify the importance of Arctic shelf regions to the global carbon cycle and provide a basis for understanding how it will

  14. Ecosystem model of the entire Beaufort Sea marine ecosystem: a tool for assessing food-web structure and ecosystem changes from 1970 to 2014

    Science.gov (United States)

    Suprenand, P. M.; Hoover, C.

    2016-02-01

    The Beaufort Sea coastal-marine ecosystem is approximately a 476,000 km2 area in the Arctic Ocean, which extends from -112.5 to -158° longitude to 67.5 to 75° latitude. Within this Arctic Ocean area the United States (Alaskan) indigenous communities of Barrow, Kaktovik, and Nuiqsut, and the Canadian (Northwest Territories) indigenous communities of Aklavik, Inuvik, Tuktoyaktuk, Paulatuk, Ulukhaktok, and Sachs Harbour, subsist by harvesting marine mammals, fish, and invertebrates from the Beaufort Sea to provide the majority of their community foods annually. The ecosystem in which the indigenous communities harvest is considered a polar habitat that includes many specialized species, such as polar bears that rely on sea-ice for foraging activities and denning, or ice algae that are attached to the cryosphere. However, the polar habitat has been experiencing a diminishing sea-ice extent, age, and seasonal duration, with concomitant increases in sea surface temperatures (SSTs), since the 1970s. Changes in sea-ice and SST have consequences to the Beaufort Sea coastal-marine ecosystem, which includes animal habitat losses, alterations to trophodynamics, and impacts to subsistence community harvesting. The present study was aimed at capturing trophodynamic changes in the Beaufort Sea coastal-marine ecosystem from 1970 to 2014 using a fitted spatial-temporal model (Ecopath with Ecosim and Ecospace) that utilizes forcing and mediation functions to describe animal/trophodynamic relationships with sea-ice and sea surface temperature, as well as individual community harvesting efforts. Model outputs reveals similar trends in animals population changes (e.g., increasing bowhead whale stock), changes in apex predator diets (e.g., polar bears eating less ringed seal), and changes in animal distributions (e.g., polar bears remaining closer to land over time). The Beaufort Sea model is a dynamic tool for Arctic Ocean natural resource management in the years to come.

  15. Apparent optical properties of the Canadian Beaufort Sea – Part 1: Observational overview and water column relationships

    Directory of Open Access Journals (Sweden)

    D. Antoine

    2013-07-01

    Full Text Available A data set of radiometric measurements collected in the Beaufort Sea (Canadian Arctic in August 2009 (Malina project is analyzed in order to describe apparent optical properties (AOPs in this sea, which has been subject to dramatic environmental changes for several decades. The two properties derived from the measurements are the spectral diffuse attenuation coefficient for downward irradiance, Kd, and the spectral remote sensing reflectance, Rrs. The former controls light propagation in the upper water column. The latter determines how light is backscattered out of the water and becomes eventually observable from a satellite ocean color sensor. The data set includes offshore clear waters of the Beaufort Basin as well as highly turbid waters of the Mackenzie River plumes. In the clear waters, we show Kd values that are much larger in the ultraviolet and blue parts of the spectrum than what could be anticipated considering the chlorophyll concentration. A larger contribution of absorption by colored dissolved organic matter (CDOM is responsible for these high Kd values, as compared to other oligotrophic areas. In turbid waters, attenuation reaches extremely high values, driven by high loads of particulate materials and also by a large CDOM content. In these two extreme types of waters, current satellite chlorophyll algorithms fail. This questions the role of ocean color remote sensing in the Arctic when Rrs from only the blue and green bands are used. Therefore, other parts of the spectrum (e.g., the red should be explored if one aims at quantifying interannual changes in chlorophyll in the Arctic from space. The very peculiar AOPs in the Beaufort Sea also advocate for developing specific light propagation models when attempting to predict light availability for photosynthesis at depth.

  16. Catalogue of polar bear (Ursus maritimus) maternal den locations in the Beaufort Sea and neighboring regions, Alaska, 1910-2010

    Science.gov (United States)

    Durner, George M.; Fischbach, Anthony S.; Amstrup, Steven C.; Douglas, David C.

    2010-01-01

    This report presents data on the approximate locations and methods of discovery of 392 polar bear (Ursus maritimus) maternal dens found in the Beaufort Sea and neighboring regions between 1910 and 2010 that are archived by the U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska. A description of data collection methods, biases associated with collection method, primary time periods, and spatial resolution are provided. Polar bears in the Beaufort Sea and nearby regions den on both the sea ice and on land. Standardized VHF surveys and satellite radio telemetry data provide a general understanding of where polar bears have denned in this region over the past 3 decades. Den observations made during other research activities and anecdotal reports from other government agencies, coastal residents, and industry personnel also are reported. Data on past polar bear maternal den locations are provided to inform the public and to provide information for natural resource agencies in planning activities to avoid or minimize interference with polar bear maternity dens.

  17. Beaufort Sea deep-water gas hydrate recovery from a seafloor mound in a region of widespread BSR occurrence

    Science.gov (United States)

    Hart, Patrick E.; Pohlman, John W.; Lorenson, T.D.; Edwards, Brian D.

    2011-01-01

    Gas hydrate was recovered from the Alaskan Beaufort Sea slope north of Camden Bay in August 2010 during a U.S. Coast Guard Cutter Healy expedition (USCG cruise ID HLY1002) under the direction of the U.S. Geological Survey (USGS). Interpretation of multichannel seismic (MCS) reflection data collected in 1977 by the USGS across the Beaufort Sea continental margin identified a regional bottom simulating reflection (BSR), indicating that a large segment of the Beaufort Sea slope is underlain by gas hydrate. During HLY1002, gas hydrate was sampled by serendipity with a piston core targeting a steep-sided bathymetric high originally thought to be an outcrop of older, exposed strata. The feature cored is an approximately 1100m diameter, 130 m high conical mound, referred to here as the Canning Seafloor Mound (CSM), which overlies the crest of a buried anticline in a region of sub-parallel compressional folds beneath the eastern Beaufort outer slope. An MCS profile shows a prominent BSR upslope and downslope from the mound. The absence of a BSR beneath the CSM and occurrence of gas hydrate near the summit indicates that free gas has migrated via deep-rooted thrust faults or by structural focusing up the flanks of the anticline to the seafloor. Gas hydrate recovered from near the CSM summit at a subbottom depth of about 5.7 meters in a water depth of 2538 m was of nodular and vein-filling morphology. Although the hydrate was not preserved, residual gas from the core liner contained >95% methane by volume when corrected for atmospheric contamination. The presence of trace C4+hydrocarbons (extrusion contributing to the development of the mound. Blister-like inflation of the seafloor caused by formation and accumulation of shallow hydrate lenses is also a likely factor in CSM growth. Pore water analysis shows the sulfate-methane transition to be very shallow (0-1 mbsf), also supporting an active high-flux interpretation. Pore water with chloride concentrations as low as 160 m

  18. A Comparison of Fish and Invertebrate Catch from Two Small Demersal Beam Trawls in the Beaufort Sea

    Science.gov (United States)

    Edenfield, L.; Iken, K.; Norcross, B.

    2016-02-01

    Both the US and Canada have conducted multi-year sampling of seafloor fauna in the Beaufort Sea using small demersal beam trawls. During the BOEM US-Canada Transboundary Fish and Lower Trophic Communities program 2012-2014, US researchers collected benthic fish and invertebrates from Pt. Barrow to the Mackenzie River mouth and Canadian scientists collected this information in the Beaufort Regional Environmental Assessment from the international border to Amundsen Gulf. Here, we compare the resulting benthic invertebrate and fish communities sampled in 2013 using the US 3-m plumb-staff beam trawl with those obtained from the Canadian beam trawl, which had larger mesh. Samples were collected at 42 locations along 6 shelf-to-slope transects (136.7 °W-146.1°W) at depths ranging from 20 to 1000 m near and west of the Mackenzie River outflow with both beam trawls. Differences in standardized catch per unit effort between gears were examined using nonparametric analyses. Based on our findings, catches between the two beam trawls can be considered indistinguishable in terms of the abundance, biomass, and overall community composition captured. Further analysis revealed that depth was a significant factor in catch composition of benthic fauna. There were no significant differences in fish sizes or taxa captured between the gears. Thus, direct comparisons of data collected from both programs can be made. This information improves our ability to examine fish and benthic invertebrate communities across the entire Beaufort Sea from Pt. Barrow in the west to Amundson Gulf in the east by allowing direct comparison between two distinct research programs.

  19. Hematology of southern Beaufort Sea polar bears (2005-2007): Biomarker for an arctic ecosystem health sentinel

    Science.gov (United States)

    Kirk, Cassandra M.; Amstrup, Steven C.; Swor, Rhonda; Holcomb, Darce; O'Hara, T. M.

    2010-01-01

    Declines in sea-ice habitats have resulted in declining stature, productivity, and survival of polar bears in some regions. With continuing sea-ice declines, negative population effects are projected to expand throughout the polar bear's range. Precise causes of diminished polar bear life history performance are unknown, however, climate and sea-ice condition change are expected to adversely impact polar bear (Ursus maritimus) health and population dynamics. As apex predators in the Arctic, polar bears integrate the status of lower trophic levels and are therefore sentinels of ecosystem health. Arctic residents feed at the apex of the ecosystem, thus polar bears can serve as indicators of human health in the Arctic. Despite their value as indicators of ecosystem welfare, population-level health data for U.S. polar bears are lacking. We present hematological reference ranges for southern Beaufort Sea polar bears. Hematological parameters in southern Beaufort Sea polar bears varied by age, geographic location, and reproductive status. Total leukocytes, lymphocytes, monocytes, eosinophils, and serum immunoglobulin G were significantly greater in males than females. These measures were greater in nonlactating females ages ???5, than lactating adult females ages ???5, suggesting that females encumbered by young may be less resilient to new immune system challenges that may accompany ongoing climate change. Hematological values established here provide a necessary baseline for anticipated changes in health as arctic temperatures warm and sea-ice declines accelerate. Data suggest that females with dependent young may be most vulnerable to these changes and should therefore be a targeted cohort for monitoring in this sentinel. ?? 2010 International Association for Ecology and Health.

  20. Hematology of southern Beaufort Sea polar bears (2005-2007): biomarker for an Arctic ecosystem health sentinel.

    Science.gov (United States)

    Kirk, Cassandra M; Amstrup, Steven; Swor, Rhonda; Holcomb, Darce; O'Hara, Todd M

    2010-09-01

    Declines in sea-ice habitats have resulted in declining stature, productivity, and survival of polar bears in some regions. With continuing sea-ice declines, negative population effects are projected to expand throughout the polar bear's range. Precise causes of diminished polar bear life history performance are unknown, however, climate and sea-ice condition change are expected to adversely impact polar bear (Ursus maritimus) health and population dynamics. As apex predators in the Arctic, polar bears integrate the status of lower trophic levels and are therefore sentinels of ecosystem health. Arctic residents feed at the apex of the ecosystem, thus polar bears can serve as indicators of human health in the Arctic. Despite their value as indicators of ecosystem welfare, population-level health data for U.S. polar bears are lacking. We present hematological reference ranges for southern Beaufort Sea polar bears. Hematological parameters in southern Beaufort Sea polar bears varied by age, geographic location, and reproductive status. Total leukocytes, lymphocytes, monocytes, eosinophils, and serum immunoglobulin G were significantly greater in males than females. These measures were greater in nonlactating females ages ≥5, than lactating adult females ages ≥5, suggesting that females encumbered by young may be less resilient to new immune system challenges that may accompany ongoing climate change. Hematological values established here provide a necessary baseline for anticipated changes in health as arctic temperatures warm and sea-ice declines accelerate. Data suggest that females with dependent young may be most vulnerable to these changes and should therefore be a targeted cohort for monitoring in this sentinel.

  1. Morphological and genetic diversity of Beaufort Sea diatoms with high contributions from the Chaetoceros neogracilis species complex.

    Science.gov (United States)

    Balzano, Sergio; Percopo, Isabella; Siano, Raffaele; Gourvil, Priscillia; Chanoine, Mélanie; Marie, Dominique; Vaulot, Daniel; Sarno, Diana

    2017-02-01

    Seventy-five diatom strains isolated from the Beaufort Sea (Canadian Arctic) in the summer of 2009 were characterized by light and electron microscopy (SEM and TEM), as well as 18S and 28S rRNA gene sequencing. These strains group into 20 genotypes and 17 morphotypes and are affiliated with the genera Arcocellulus, Attheya, Chaetoceros, Cylindrotheca, Eucampia, Nitzschia, Porosira, Pseudo-nitzschia, Shionodiscus, Thalassiosira, and Synedropsis. Most of the species have a distribution confined to the northern/polar area. Chaetoceros neogracilis and Chaetoceros gelidus were the most represented taxa. Strains of C. neogracilis were morphologically similar and shared identical 18S rRNA gene sequences, but belonged to four distinct genetic clades based on 28S rRNA, ITS-1 and ITS-2 phylogenies. Secondary structure prediction revealed that these four clades differ in hemi-compensatory base changes (HCBCs) in paired positions of the ITS-2, suggesting their inability to interbreed. Reproductively isolated C. neogracilis genotypes can thus co-occur in summer phytoplankton communities in the Beaufort Sea. C. neogracilis generally occurred as single cells but also formed short colonies. It is phylogenetically distinct from an Antarctic species, erroneously identified in some previous studies as C. neogracilis, but named here as Chaetoceros sp. This work provides taxonomically validated sequences for 20 Arctic diatom taxa, which will facilitate future metabarcoding studies on phytoplankton in this region. © 2016 Phycological Society of America.

  2. MIZMAS: Modeling the Evolution of Ice Thickness and Floe Size Distributions in the Marginal Ice Zone of the Chukchi and Beaufort Seas

    Science.gov (United States)

    2015-09-30

    Size Distributions in the Marginal Ice Zone of the Chukchi and Beaufort Seas Jinlun Zhang Applied Physics Laboratory, University of Washington...high-resolution coupled sea ice–ocean modeling and assimilation system that is capable of accurately predicting sea ice conditions in the marginal ice...the scientific objectives, we plan to develop, implement, and validate a new coupled ice– ocean Marginal Ice Zone Modeling and Assimilation System

  3. Considerations in the design of effects monitoring strategies: Beaufort Sea case study

    National Research Council Canada - National Science Library

    Thomas, D. J

    1992-01-01

    .... En prevision du developpement futur des forgaes offshore dans la mer de Beaufort, il est tout a fait indique d'effectuer des etudes de surveillance portant sur des points d'incertitude associes aux previsions des incidences environnementales, d'evaluer l'efficacite des mesures correctives et de rassurer le public en.

  4. Quaternary sedimentation of the Alaskan Beaufort shelf: Influence of regional tectonics, fluctuating sea levels, and glacial sediment sources

    Science.gov (United States)

    Dinter, D.A.

    1985-01-01

    The offshore stratigraphy of the Quaternary Gubik Formation of Arctic Alaska has been studied on high-resolution seismic profiles with a maximum sub-seafloor penetration of about 100 m. In general, marine transgressive subunits of the Gubik Formation are wedge-shaped on the shelf, thickening slightly seaward to the shelf break, beyond which they are offset by landslides and slumps. Beneath the eastern third of the Alaskan Beaufort shelf, active folding has created two persistent structural depressions, the Eastern and Western Wedge Terranes, in which the wedge morphology is especially well developed. The youngest transgressive marine wedge, which was deposited in such a way as to fill these depressions, leaving a generally flat present-day shelf surface, is inferred to be late Wisconsin or younger in age because it overlies a prominent disconformity interpreted to have been formed during the late Wisconsin glacial sea-level minimum. The thickness of this youngest wedge, Unit A, locally exceeds 40 m on the outer shelf, yet apparently relict gravel deposits collected from its seabed surface indicate that the depositional rate is presently quite low on the middle and outer shelf. Lithologies of the gravels are exotic to Alaska, but similar to suites exposed in the Canadian Arctic Islands. These observations suggest a depositional scenario in which the retreating Laurentide Ice Sheet shed sediment-laden icebergs from the Canadian Arctic Islands into the Arctic Ocean following the late Wisconsin glacial maximum. These bergs were then rafted westward by the Beaufort Gyre and grounded on the Alaskan shelf by northeasterly prevailing winds. Especially large numbers of bergs accumulated in the wedge terrane embayments-created as sea level rose-and melted there, filling the embayments with their sedimentary cargo. As glacial retreat slowed, depositional rates on the shelf dwindled. This mode of deposition in the Alaskan Beaufort wedge terranes may be typical of early post

  5. Sharing Remote and Local Information for Tracking Spring Breakup in the Mackenzie Delta and Beaufort Sea

    Science.gov (United States)

    Forbes, D. L.; Whalen, D.; Fraser, P.

    2015-12-01

    The Mackenzie Delta is the second largest on the Arctic Ocean, covering 13 000 km2. The annual flood regime in the delta is dominated by the spring snowmelt freshet and associated ice breakup, as water from the south arrives in the ice-covered delta and spreads over bottomfast and adjacent floating sea ice at the delta front. The complex processes of water-ice interaction, flow partitioning, and overbank flooding to replenish waters in 43 000 delta lakes threaten community, transportation, subsistence, and energy infrastructure in the delta. The annual breakup season is a time of rejuvenation, excitement, and anxiety for delta residents and stakeholders. To track the progress of breakup and meet the need for knowledge dissemination to the local communities, a Mackenzie-Beaufort breakup newsletter has been produced by Natural Resources Canada on a quasi-daily basis during the May-June spring flood season for 10 years, and distributed to an e-mail list that grew to over 300 subscribers. This provides near real-time tracking of water levels and breakup using on-line gauges (Environment Canada), daily MODIS satellite imagery (NASA), Landsat imagery (USGS) and intermittent radar imagery (various sources). In earlier years, information was also supplied from field programs operating in the delta during breakup, but changing priorities and funding have reduced the number of outside researchers present during these critical weeks. Meanwhile the number of local contributors has grown, providing observations and photographs to share with the local, regional and global readership. In this way the newsletter evolved into a two-way communication tool and community portal. The newsletter is a chronicle of each breakup season and a key resource for territorial and municipal managers, subsistence organizations, and emergency response agencies, with routine requests for specific imagery in areas of concern. With the completion of 10 years under the present model, we are exploring

  6. Long-distance swimming by polar bears (Ursus maritimus) of the southern Beaufort Sea during years of extensive open water

    Science.gov (United States)

    2014-01-01

    Polar bears (Ursus maritimus Phipps, 1774) depend on sea ice for catching marine mammal prey. Recent sea-ice declines have been linked to reductions in body condition, survival, and population size. Reduced foraging opportunity is hypothesized to be the primary cause of sea-ice-linked declines, but the costs of travel through a deteriorated sea-ice environment also may be a factor. We used movement data from 52 adult female polar bears wearing Global Positioning System (GPS) collars, including some with dependent young, to document long-distance swimming (>50 km) by polar bears in the southern Beaufort and Chukchi seas. During 6 years (2004-2009), we identified 50 long-distance swims by 20 bears. Swim duration and distance ranged from 0.7 to 9.7 days (mean = 3.4 days) and 53.7 to 687.1 km (mean = 154.2 km), respectively. Frequency of swimming appeared to increase over the course of the study. We show that adult female polar bears and their cubs are capable of swimming long distances during periods when extensive areas of open water are present. However, long-distance swimming appears to have higher energetic demands than moving over sea ice. Our observations suggest long-distance swimming is a behavioral response to declining summer sea-ice conditions.

  7. Origin of pingo-like features on the Beaufort Sea shelf and their possible relationship to decomposing methane gas hydrates

    Science.gov (United States)

    Paull, C.K.; Ussler, W.; Dallimore, S.R.; Blasco, S.M.; Lorenson, T.D.; Melling, H.; Medioli, B.E.; Nixon, F.M.; McLaughlin, F.A.

    2007-01-01

    The Arctic shelf is currently undergoing dramatic thermal changes caused by the continued warming associated with Holocene sea level rise. During this transgression, comparatively warm waters have flooded over cold permafrost areas of the Arctic Shelf. A thermal pulse of more than 10??C is still propagating down into the submerged sediment and may be decomposing gas hydrate as well as permafrost. A search for gas venting on the Arctic seafloor focused on pingo-like-features (PLFs) on the Beaufort Sea Shelf because they may be a direct consequence of gas hydrate decomposition at depth. Vibracores collected from eight PLFs had systematically elevated methane concentrations. ROV observations revealed streams of methane-rich gas bubbles coming from the crests of PLFs. We offer a scenario of how PLFs may be growing offshore as a result of gas pressure associated with gas hydrate decomposition. Copyright 2007 by the American Geophysical Union.

  8. Dissolved methane in the Beaufort Sea and the Arctic Ocean, 1992-2009; sources and atmospheric flux

    Science.gov (United States)

    Lorenson, Thomas D.; Greinert, Jens; Coffin, Richard B.

    2016-01-01

    Methane concentration and isotopic composition was measured in ice-covered and ice-free waters of the Arctic Ocean during eleven surveys spanning the years of 1992-1995 and 2009. During ice-free periods, methane flux from the Beaufort shelf varies from 0.14 to 0.43 mg CH4 m-2 day-1. Maximum fluxes from localized areas of high methane concentration are up to 1.52 mg CH4 m-2 day-1. Seasonal buildup of methane under ice can produce short-term fluxes of methane from the Beaufort shelf that varies from 0.28 to 1.01 to mg CH4 m-2 day-1. Scaled-up estimates of minimum methane flux from the Beaufort Sea and pan-Arctic shelf for both ice-free and ice-covered periods range from 0.02 Tg CH4 yr-1 and 0.30 Tg CH4 yr-1 respectively to maximum fluxes of 0.18 Tg CH4 yr-1 and 2.2 Tg CH4 yr-1 respectively. A methane flux of 0.36 Tg CH4 yr-1from the deep Arctic Ocean was estimated using data from 1993-94. The flux can be as much as 2.35 Tg CH4 yr-1 estimated from maximum methane concentrations and wind speeds of 12 m/s, representing only 0.42% of the annual atmospheric methane budget of ~560 Tg CH4 yr-1. There were no significant changes in methane fluxes during the time period of this study. Microbial methane sources predominate with minor influxes from thermogenic methane offshore Prudhoe Bay and the Mackenzie River delta and may include methane from gas hydrate. Methane oxidation is locally important on the shelf and is a methane sink in the deep Arctic Ocean.

  9. Effects of capturing and collaring on polar bears: findings from long-term research on the southern Beaufort Sea population

    Science.gov (United States)

    Rode, Karyn D.; Pagano, Anthony M.; Bromaghin, Jeffrey F.; Atwood, Todd C.; Durner, George M.; Simac, Kristin S.; Amstrup, Steven C.

    2014-01-01

    Context: The potential for research methods to affect wildlife is an increasing concern among both scientists and the public. This topic has a particular urgency for polar bears because additional research is needed to monitor and understand population responses to rapid loss of sea ice habitat.Aims: This study used data collected from polar bears sampled in the Alaska portion of the southern Beaufort Sea to investigate the potential for capture to adversely affect behaviour and vital rates. We evaluated the extent to which capture, collaring and handling may influence activity and movement days to weeks post-capture, and body mass, body condition, reproduction and survival over 6 months or more.Methods: We compared post-capture activity and movement rates, and relationships between prior capture history and body mass, body condition and reproductive success. We also summarised data on capture-related mortality.Key results: Individual-based estimates of activity and movement rates reached near-normal levels within 2–3 days and fully normal levels within 5 days post-capture. Models of activity and movement rates among all bears had poor fit, but suggested potential for prolonged, lower-level rate reductions. Repeated captures was not related to negative effects on body condition, reproduction or cub growth or survival. Capture-related mortality was substantially reduced after 1986, when immobilisation drugs were changed, with only 3 mortalities in 2517 captures from 1987–2013.Conclusions: Polar bears in the southern Beaufort Sea exhibited the greatest reductions in activity and movement rates 3.5 days post-capture. These shorter-term, post-capture effects do not appear to have translated into any long-term effects on body condition, reproduction, or cub survival. Additionally, collaring had no effect on polar bear recovery rates, body condition, reproduction or cub survival.Implications: This study provides empirical evidence that current capture

  10. Partial pressure (or fugacity) of carbon dioxide, salinity and SEA SURFACE TEMPERATURE collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from Marcus G. Langseth in the Arctic Ocean, Beaufort Sea and others from 2010-05-07 to 2013-06-25 (NODC Accession 0109901)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0109901 includes Surface underway data collected from Marcus G. Langseth in the Arctic Ocean, Beaufort Sea, Bering Sea, Caribbean Sea, Cordell Bank...

  11. Evaluation of the anthropogenic radionuclide concentrations in sediments and fauna collected in the Beaufort Sea and northern Alaska

    International Nuclear Information System (INIS)

    Efurd, D.W.; Miller, G.G.; Rokop, D.J.

    1997-07-01

    This study was performed to establish a quality controlled data set about the levels of radio nuclide activity in the environment and in selected biota in the U.S. Arctic. Sediment and biota samples were collected by the National Oceanic and Atmospheric Administration (NOAA), the National Biological Service, and the North Slope Borough's Department of Wildlife Management to determine the impact of anthropogenic radionuclides in the Arctic. The results summarized in this report are derived from samples collected in northwest Alaska with emphasis on species harvested for subsistence in Barrow, Alaska. Samples were analyzed for the anthropogenic radionuclides 90 Sr, 137 Cs, 238 Pu, 239 Pu, 240 Pu and 241 Am. The naturally occurring radionuclides 40 K, 212 Pb and 214 Pb were also measured. One goal of this study was to determine the amounts of anthropogenic radionuclides present in the Beaufort Sea. Sediment samples were isotopically fingerprinted to determine the sources of radio nuclide activities. Biota samples of subsistence and ecological value were analyzed to search for evidence of bio-accumulation of radionuclides and to determine the radiation exposures associated with subsistence living in northern Alaska. The anthropogenic radio nuclide content of sediments collected in the Beaufort Sea was predominantly the result of the deposition of global fallout. No other sources of anthropogenic radionuclides could be conclusively identified in the sediments. The anthropogenic radio nuclide concentrations in fish, birds and mammals were very low. Assuming that ingestion of food is an important pathway leading to human contact with radioactive contaminants and given the dietary patterns in coastal Arctic communities, it can be surmised that marine food chains are presently not significantly affected

  12. Atmospheric Profiles, Clouds and the Evolution of Sea Ice Cover in the Beaufort and Chukchi Seas: Atmospheric Observations and Modeling as Part of the Seasonal Ice Zone Reconnaissance Surveys

    Science.gov (United States)

    2017-06-04

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Atmospheric Profiles, Clouds, and the Evolution of Sea Ice...Cover in the Beaufort and Chukchi Seas: Atmospheric Observations and Modeling as Part of the Seasonal Ice Zone Reconnaissance Surveys Axel...TERM GOALS The goal of this project is to examine the role of sea-ice and atmospheric interactions in the retreat of the SIZ. As sea ice retreats

  13. Profile data from CTD casts aboard the F/V Ocean Explorer in the Arctic Ocean and Beaufort Sea from 2008-08-06 to 2008-08-22 (NODC Accession 0001920)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This profile data aboard the F/V Ocean Explorer in the Arctic Ocean and Beaufort Sea from August 6, 2008 to August 22, 2008 was supported by the Minerals Management...

  14. Plankton and other data from net casts in the Beaufort Sea from the USCGC GLACIER and other platforms from 04 August 1972 to 17 May 1979 (NODC Accession 8000587)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Plankton and other data were collected using net casts in the Beaufort Sea from the USCGC GLACIER and other platforms from 04 August 1972 to 17 May 1979. Data were...

  15. Effluent - discharge descriptions and other data collected from several platforms using salinometer and other instruments in the Beaufort Sea from 07 August 1985 to 01 September 1985 (NODC Accession 8600317)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — F144 data were collected using salinometer and other instruments in the Beaufort Sea from several platforms. Data were collected from 07 August 1985 to 01 September...

  16. Marine mammal observations collected by aircraft and ship and submitted as part of the ConocoPhillips and Shell Joint Monitoring Program in the Chukchi and Beaufort Seas, 2006-2010 (NODC Accession 0120532)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains vessel- and aircraft-based mammal sightings data and associated environmental data collected in the Chukchi and Beaufort seas during the open...

  17. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from HEALY in the Arctic Ocean and Beaufort Sea from 2003-09-11 to 2003-10-18 (NODC Accession 0115676)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0115676 includes biological, chemical, discrete sample, optical, physical and profile data collected from HEALY in the Arctic Ocean and Beaufort Sea...

  18. Acoustics short-term passive monitoring using sonobuoys in the Bering, Chukchi, and Western Beaufort Seas conducted by Alaska Fisheries Scientific Center, National Marine Mammal Laboratory from 2007-08-01 to 2015-09-28 (NCEI Accession 0138863)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Mammal Laboratory (NMML) has conducted passive acoustic monitoring in the Bering, Chukchi, and Western Beaufort Seas to determine spatio-temporal...

  19. Evolution Of Late Holocene Sea-Surface Parameters In The Beaufort Sea Area (Mackenzie Slope, Canadian Arctic): Insights From CASES 2004-804-803 Cores

    Science.gov (United States)

    Rochon, A.; Bringué, M.

    2009-05-01

    This study aims at reconstructing late Holocene sea-surface parameters in the Beaufort Sea area (Western Canadian Arctic) on the basis of sedimentary cores collected over the Mackenzie Slope. Piston, trigger and box cores were sampled at station 803 in 2004 aboard the CCGS Amundsen (CASES) at 218 m water depth. Sedimentation at this particular location is influenced by both the Beaufort gyre and the Mackenzie River, whose sedimentary discharge is by far the largest among all other Arctic rivers. The chronology of the piston core is constrained by 4 AMS-14C dates, as the sedimentation rate in the box core is assessed from 210Pb data. We obtain a continuous composite sequence covering the last 4600 years, with a sedimentation rate of ˜140 cm/kyr. Palynological data reveal that dinocyst assemblages are dominated by Operculodinium centrocarpum (mean of 43.3%), with the accompanying taxa Brigantedinium spp. (19.6%), Islandinium minutum (15.6%) and cysts of Pentapharsodinium dalei (13.7%). Four zones have been established on the basis of dinocyst relative abundances, with the following key taxa. Zone I (4600-4000 cal BP): high relative abundances of cysts of P. dalei (mean of 14.9%) and I. minutum var. cezare (up to 8.9%); zone II (4000-2600 cal BP): high abundances of Spiniferites frigidus/elongatus (up to 7.3%); zone III (2600-1600 cal BP): well- represented heterotrophic taxa Brigantedinium spp. (30.8%) and cysts of Polykrikos sp. arctic/quadratus (up to 4.2%); zone IV (1600 cal BP - present): high relative abundances of I. minutum (mean of 19.8%) and cysts of P. dalei (17.3%). Quantitative reconstructions of sea-surface parameters indicate relatively stable conditions from 4600 to 1600 cal BP. Conversely, a trend of increasing summer (August) sea-surface temperature (from ˜5° C to ˜6° C; actual value = 6° C), increasing salinity (from ˜20 to ˜26 psu; modern value = 19 psu) and decreasing sea-ice cover (from ˜9 to 8 month/yr; actual value = 10) is observed

  20. Atmospheric Profiles, Clouds and the Evolution of Sea Ice Cover in the Beaufort and Chukchi Seas: Atmospheric Observations and Modeling as Part of the Seasonal Ice Zone Reconnaissance Surveys

    Science.gov (United States)

    2017-06-04

    Evolution of Sea Ice Sb. GRANT NUMBER N000 1 4-1 2- 1-0232 Sc. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Sd. PROJECT NUMBER Axel Schweiger Se. TASK NUMBER...Clouds, and the Evolution of Sea Ice Cover in the Beaufort and Chukchi Seas: Atmospheric Observations and Modeling as Part of the Seasonal Ice Zone...concentrations and ocean temperatures. These changes in turn will affect the evolution of the SIZ. An appropriate representation ofthis feedback loop in

  1. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, Coulometer for DIC measurement and other instruments from MIRAI in the Beaufort Sea and Bering Sea from 2006-08-21 to 2006-09-29 (NODC Accession 0112268)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0112268 includes chemical, discrete sample, optical, physical and profile data collected from MIRAI in the Beaufort Sea and Bering Sea from 2006-08-21...

  2. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, Coulometer for DIC measurement and other instruments from the ODEN in the Arctic Ocean, Beaufort Sea and Bering Sea from 2005-08-19 to 2005-09-25 (NODC Accession 0108129)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0108129 includes chemical, discrete sample, physical and profile data collected from ODEN in the Arctic Ocean, Beaufort Sea and Bering Sea from...

  3. Partial pressure (or fugacity) of carbon dioxide, salinity and SEA SURFACE TEMPERATURE collected from underway - surface observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from the HEALY in the Arctic Ocean, Beaufort Sea and others from 2011-05-17 to 2012-10-26 (NODC Accession 0083197)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0083197 includes chemical, physical and underway - surface data collected from HEALY in the Arctic Ocean, Beaufort Sea, Bering Sea, Coastal Waters of...

  4. Partial pressure (or fugacity) of carbon dioxide, salinity and SEA SURFACE TEMPERATURE collected from underway - surface observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from the NATHANIEL B. PALMER in the Arctic Ocean, Beaufort Sea and others from 1994-11-04 to 2012-08-31 (NODC Accession 0083189)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0083189 includes chemical, physical and underway - surface data collected from NATHANIEL B. PALMER in the Arctic Ocean, Beaufort Sea, Bering Sea,...

  5. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from HEALY in the Arctic Ocean, Beaufort Sea and Bering Sea from 2015-08-09 to 2015-10-13 (NCEI Accession 0156924)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0156924 includes chemical, discrete sample, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and Bering Sea from...

  6. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, Coulometer for DIC measurement and other instruments from the MIRAI in the Arctic Ocean, Beaufort Sea and Bering Sea from 2000-08-03 to 2000-10-13 (NODC Accession 0112352)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0112352 includes chemical, discrete sample, physical and profile data collected from MIRAI in the Arctic Ocean, Beaufort Sea and Bering Sea from...

  7. Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from JAKOV SMIRNITSKIY in the Beaufort Sea, East Siberian Sea and others from 2008-08-15 to 2008-09-16 (NODC Accession 0108368)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0108368 includes chemical, discrete sample, physical and profile data collected from JAKOV SMIRNITSKIY in the Beaufort Sea, East Siberian Sea, Kara...

  8. Prevalence and spatio-temporal variation of an alopecia syndrome in polar bears (Ursus maritimus) of the southern Beaufort Sea

    Science.gov (United States)

    Atwood, Todd C.; Peacock, Elizabeth; Burek, K.A.; Shearn-Bochsler, Valerie I.; Bodenstein, Barbara L.; Beckmen, Kimberlee B.; Durner, George M.

    2015-01-01

    Alopecia (hair loss) has been observed in several marine mammal species and has potential energetic consequences for sustaining a normal core body temperature, especially for Arctic marine mammals routinely exposed to harsh environmental conditions. Polar bears (Ursus maritimus) rely on a thick layer of adipose tissue and a dense pelage to ameliorate convective heat loss while moving between sea ice and open water. From 1998 to 2012, we observed an alopecia syndrome in polar bears from the southern Beaufort Sea of Alaska that presented as bilaterally asymmetrical loss of guard hairs and thinning of the undercoat around the head, neck, and shoulders, which, in severe cases, was accompanied by exudation and crusted skin lesions. Alopecia was observed in 49 (3.45%) of the bears sampled during 1,421 captures, and the apparent prevalence varied by years with peaks occurring in 1999 (16%) and 2012 (28%). The probability that a bear had alopecia was greatest for subadults and for bears captured in the Prudhoe Bay region, and alopecic individuals had a lower body condition score than unaffected individuals. The cause of the syndrome remains unknown and future work should focus on identifying the causative agent and potential effects on population vital rates.

  9. Prevalence and spatio-temporal variation of an alopecia syndrome in polar bears (Ursus maritimus) of the southern Beaufort Sea.

    Science.gov (United States)

    Atwood, Todd; Peacock, Elizabeth; Burek-Huntington, Kathy; Shearn-Bochsler, Valerie; Bodenstein, Barbara; Beckmen, Kimberlee; Durner, George

    2015-01-01

    Alopecia (hair loss) has been observed in several marine mammal species and has potential energetic consequences for sustaining a normal core body temperature, especially for Arctic marine mammals routinely exposed to harsh environmental conditions. Polar bears (Ursus maritimus) rely on a thick layer of adipose tissue and a dense pelage to ameliorate convective heat loss while moving between sea ice and open water. From 1998 to 2012, we observed an alopecia syndrome in polar bears from the southern Beaufort Sea of Alaska that presented as bilaterally asymmetrical loss of guard hairs and thinning of the undercoat around the head, neck, and shoulders, which, in severe cases, was accompanied by exudation and crusted skin lesions. Alopecia was observed in 49 (3.45%) of the bears sampled during 1,421 captures, and the apparent prevalence varied by years with peaks occurring in 1999 (16%) and 2012 (28%). The probability that a bear had alopecia was greatest for subadults and for bears captured in the Prudhoe Bay region, and alopecic individuals had a lower body condition score than unaffected individuals. The cause of the syndrome remains unknown and future work should focus on identifying the causative agent and potential effects on population vital rates.

  10. Aerial surveys of endangered whales in the Alaskan Chukchi and western Beaufort Seas, 1990. Final report, Oct-Nov 90

    International Nuclear Information System (INIS)

    Moore, S.E.; Clarke, J.T.

    1991-06-01

    In keeping with the National Environmental Policy Act (1969), the Marine Mammal Protection Act (1972) and the Endangered Species Act (1973), the OCS Lands Act Amendments (1978) established a management policy that included studies in OCS lease sale areas to ascertain potential environmental impacts of oil and gas development on OCS marine coastal environments. The Minerals Management Service (MMS) is the agency responsible for these studies and for the leasing of submerged Federal lands. The report summarizes the 1990 investigations of the distribution, abundance, migration, behavior and habitat relationships of endangered whales in the Alaskan Chukchi and western Beaufort Seas (hereafter, study area); 1990 was the second of a three year (1989-91) study. The Bering Sea stock of bowhead whales (Balaena mysticetus) was the principal species studied, with incidental sightings of all other marine mammals routinely recorded. The 1990 season was compromised by circumstances that restricted the availability of the survey aircraft (Grumman Goose, model G21G) to the period 26 October - 7 November; opportunistic surveys were flown in the study area from 3-25 October. In 1990, there were 14 sightings of 19 bowheads from 9-29 October; 5 whales, including 2 calves, were seen north of the study area. One gray whale, 110 belukhas and 53 polar bears were also seen. Over nine survey seasons (1982-90), there were 240 sightings of 520 bowhead whales and 148 sightings of 398 gray whales

  11. Modeling plankton ecosystem functioning and nitrogen fluxes in the oligotrophic waters of the Beaufort Sea, Arctic Ocean: a focus on light-driven processes

    Directory of Open Access Journals (Sweden)

    V. Le Fouest

    2013-07-01

    Full Text Available The Arctic Ocean (AO undergoes profound changes of its physical and biotic environments due to climate change. In some areas of the Beaufort Sea, the stronger haline stratification observed in summer alters the plankton ecosystem structure, functioning and productivity, promoting oligotrophy. A one-dimension (1-D physical–biological coupled model based on the large multiparametric database of the Malina project in the Beaufort Sea was used (i to infer the plankton ecosystem functioning and related nitrogen fluxes and (ii to assess the model sensitivity to key light-driven processes involved in nutrient recycling and phytoplankton growth. The coupled model suggested that ammonium photochemically produced from photosensitive dissolved organic nitrogen (i.e., photoammonification process was a necessary nitrogen source to achieve the observed levels of microbial biomass and production. Photoammonification directly and indirectly (by stimulating the microbial food web activity contributed to 70% and 18.5% of the 0–10 m and whole water column, respectively, simulated primary production (respectively 66% and 16% for the bacterial production. The model also suggested that variable carbon to chlorophyll ratios were required to simulate the observed herbivorous versus microbial food web competition and realistic nitrogen fluxes in the Beaufort Sea oligotrophic waters. In face of accelerating Arctic warming, more attention should be paid in the future to the mechanistic processes involved in food webs and functional group competition, nutrient recycling and primary production in poorly productive waters of the AO, as they are expected to expand rapidly.

  12. Tectonique dans la région de la mer de Beaufort (Arctique canadien (résumé Tectonism in the Beaufort Sea - Region of Arctic Canada (Abstract

    Directory of Open Access Journals (Sweden)

    Mroszczak W. E.

    2006-10-01

    Full Text Available Le delta de la Mackenzie et la mer de Beaufort qui en sont encore au début de l'exploration, peuvent devenir une région pétrolière majeure dans les années 1980. Ce vaste bassin tertiaire est situé dans un environnement arctique ; il a demandé et nécessitera dans l'avenir de nouvelles technologies pour développer et produire les hydrocarbures si l'exploration est couronnée de succès. L'exploration pour l'huile et le gaz a été active dans cette région depuis 1965 bien que les facteurs climatiques et économiques aient eu tendance à freiner cette exploration, particulièrement en mer. L'auteur présente un bref historique des recherches comprenant les derniers résultats des sondage dans la mer de Beaufort forés par Dome Petroleum et ses partenaires. On discute aussi l'origine des structures en mer, en commentant les données sismiques. La structuration est considérée comme le résultat d'une sédimentation rapide de clastiques au Tertiaire dans un bassin dont le substratum serait formé d'une épaisse série d'argiles sous-compactées d'âge jurassique ou crétacé. The Mackenzie Delta and offshore Beaufort Sea Region which is at a very early stage of exploration, may become a major source of hydrocarbons in the 1980's This large Tertiary basin is situated in an Arctic environment and has required, and will require in the future, new technology to develop and produce hydrocarbons if exploration is successful. Exploration for oil and gas has been active in the area since 1965 with climatic and economic factors contributing ta a slow pace of exploration, particularly in the offshore area. A brief history of exploration with and update of the latest results of drilling in the Beaufort by Dome Petroleum and its partners is presented. Using seismic data, the genesis of structures found in the offshore area is discussed. These are believed to be the result of rapid Tertiary clastic deposition in a basin underlain by a thick section of

  13. Demographic and temporal variations in immunity and condition of polar bears (Ursus maritimus) from the southern Beaufort Sea.

    Science.gov (United States)

    Neuman-Lee, Lorin A; Terletzky, Patricia A; Atwood, Todd C; Gese, Eric M; Smith, Geoffrey D; Greenfield, Sydney; Pettit, John; French, Susannah S

    2017-06-01

    Assessing the health and condition of animals in their natural environment can be problematic. Many physiological metrics, including immunity, are highly influenced by specific context and recent events to which researchers may be unaware. Thus, using a multifaceted physiological approach and a context-specific analysis encompassing multiple time scales can be highly informative. Ecoimmunological tools in particular can provide important indications to the health of animals in the wild. We collected blood and hair samples from free-ranging polar bears (Ursus maritimus) in the southern Beaufort Sea and examined the influence of sex, age, and reproductive status on metrics of immunity, stress, and body condition during 2013-2015. We examined metrics of innate immunity (bactericidal ability and lysis) and stress (hair cortisol, reactive oxygen species, and oxidative barrier), in relation to indices of body condition considered to be short term (urea to creatinine ratio; UC ratio) and long term (storage energy and body mass index). We found the factors of sex, age, and reproductive status of the bear were critical for interpreting different physiological metrics. Additionally, the metrics of body condition were important predictors for stress indicators. Finally, many of these metrics differed between years, illustrating the need to examine populations on a longer time scale. Taken together, this study demonstrates the complex relationship between multiple facets of physiology and how interpretation requires us to examine individuals within a specific context. © 2017 Wiley Periodicals, Inc.

  14. Relationships between High River Discharge, Upwelling Events, and Bowhead Whale (Balaena mysticetus) Occurrence in the Central Alaskan Beaufort Sea

    Science.gov (United States)

    Clarke, J.; Okkonen, S. R.; Potter, R. A.

    2016-02-01

    Aerial surveys of bowhead whales have been conducted in September in the central Alaskan Beaufort Sea (144°W-150°W) for several decades. These surveys, co-managed by BOEM and NOAA, have documented bowhead whale distribution that is almost exclusively on the continental shelf, generally from feeding behavior occasionally observed. In September 2014, several hundred bowhead whales were observed feeding on several occasions within a few kilometers of local barrier islands. This is an unusual situation that has been observed in September in only one other year (1997). To investigate local conditions that might be conducive to increased bowhead whale occurrence, freshwater discharge data from the Sagavanirktok and Kuparak rivers, surface wind data, and suspended sediment data obtained from MODIS satellite imagery were analyzed and compared to bowhead whale observations for September 1989-2014. Results indicate that anomalously high freshwater river discharge coupled with prior upwelling events, based on surface winds >5.4 m s-1, may combine to promote the aggregation of bowhead whale prey on the shallow shelf. When these two conditions were met, whales were sighted more frequently, were more likely to be in groups of ≥2 animals, and be closer to shore. Conversely, when either of the two conditions was not met, whales were sighted less frequently, more likely to be single animals, and be farther from shore. These results underscore annual variation during the bowhead whale fall migration and the physical oceanography processes that may be related to whale distribution and behavior.

  15. Mercury concentrations in Southern Beaufort Sea polar bears: variation based on stable isotopes of carbon and nitrogen.

    Science.gov (United States)

    Cardona-Marek, Tamara; Knott, Katrina K; Meyer, Benjamin E; O'Hara, Todd M

    2009-07-01

    Total Hg concentration was measured in hair and whole blood of 52 adult Southern Beaufort Sea polar bears (Ursus maritimus) captured in the spring of 2005. Stable isotopic signatures (i.e., 13C/12C, delta13C; 15N/14N, delta15N) in hair and two blood compartments (packed blood cells/clot and serum) were determined to assess the variation of Hg concentrations among polar bears in relation to their feeding ecology and other biological factors. Concentrations of Hg in hair and blood (2.2-23.9 microg/g dry wt and 0.007-0.213 microg/g wet wt, respectively) were within the range of values previously reported for polar bears in Canada and East Greenland. Mercury concentration in hair from females was higher than that in hair from males, and concentration was related to interactions between delta13C, delta15N, and longitude of capture location. Mercury concentrations in hair were inversely correlated to delta13C in hair and blood, suggesting that polar bears with greater total Hg concentrations fed more on pelagic prey, such as ringed seals or beluga whale, than on benthic prey. Variability in Hg concentrations in polar bear hair and blood may be the result of intraspecific or regional variation in prey selection rather than strictly trophic level interactions.

  16. Habitat use and foraging patterns of molting male Long-tailed Ducks in lagoons of the central Beaufort Sea, Alaska

    Science.gov (United States)

    Flint, Paul L.; Reed, John; Deborah Lacroix,; Richard Lanctot,

    2016-01-01

    From mid-July through September, 10 000 to 30 000 Long-tailed Ducks (Clangula hyemalis) use the lagoon systems of the central Beaufort Sea for remigial molt. Little is known about their foraging behavior and patterns of habitat use during this flightless period. We used radio transmitters to track male Long-tailed Ducks through the molt period from 2000 to 2002 in three lagoons: one adjacent to industrial oil field development and activity and two in areas without industrial activity. We found that an index to time spent foraging generally increased through the molt period. Foraging, habitat use, and home range size showed similar patterns, but those patterns were highly variable among lagoons and across years. Even with continuous daylight during the study period, birds tended to use offshore areas during the day for feeding and roosted in protected nearshore waters at night. We suspect that variability in behaviors associated with foraging, habitat use, and home range size are likely influenced by availability of invertebrate prey. Proximity to oil field activity did not appear to affect foraging behaviors of molting Long-tailed Ducks.

  17. Demographic and temporal variations in immunity and condition of polar bears (Ursus maritimus) from the southern Beaufort Sea

    Science.gov (United States)

    Neuman-Lee, Lorin; Terletzky, Patricia; Atwood, Todd C.; Gese, Eric; Smith, Geoffrey; Greenfield, Sydney; Pettit, John; French, Susannah

    2017-01-01

    Assessing the health and condition of animals in their natural environment can be problematic. Many physiological metrics, including immunity, are highly influenced by specific context and recent events to which researchers may be unaware. Thus, using a multifaceted physiological approach and a context-specific analysis encompassing multiple time scales can be highly informative. Ecoimmunological tools in particular can provide important indications to the health of animals in the wild. We collected blood and hair samples from free-ranging polar bears (Ursus maritimus) in the southern Beaufort Sea and examined the influence of sex, age, and reproductive status on metrics of immunity, stress, and body condition during 2013–2015. We examined metrics of innate immunity (bactericidal ability and lysis) and stress (hair cortisol, reactive oxygen species, and oxidative barrier), in relation to indices of body condition considered to be short term (urea to creatinine ratio; UC ratio) and long term (storage energy and body mass index). We found the factors of sex, age, and reproductive status of the bear were critical for interpreting different physiological metrics. Additionally, the metrics of body condition were important predictors for stress indicators. Finally, many of these metrics differed between years, illustrating the need to examine populations on a longer time scale. Taken together, this study demonstrates the complex relationship between multiple facets of physiology and how interpretation requires us to examine individuals within a specific context.

  18. Genetic variation, relatedness, and effective population size of polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska

    Science.gov (United States)

    Cronin, Matthew A.; Amstrup, Steven C.; Talbot, Sandra L.; Sage, George K.; Amstrup, Kristin S.

    2009-01-01

    Polar bears (Ursus maritimus) are unique among bears in that they are adapted to the Arctic sea ice environment. Genetic data are useful for understanding their evolution and can contribute to management. We assessed parentage and relatedness of polar bears in the southern Beaufort Sea, Alaska, with genetic data and field observations of age, sex, and mother–offspring and sibling relationships. Genotypes at 14 microsatellite DNA loci for 226 bears indicate that genetic variation is comparable to other populations of polar bears with mean number of alleles per locus of 7.9 and observed and expected heterozygosity of 0.71. The genetic data verified 60 field-identified mother–offspring pairs and identified 10 additional mother–cub pairs and 48 father–offspring pairs. The entire sample of related and unrelated bears had a mean pairwise relatedness index (rxy) of approximately zero, parent–offspring and siblings had rxy of approximately 0.5, and 5.2% of the samples had rxy values within the range expected for parent-offspring. Effective population size (Ne= 277) and the ratio of Ne to total population size (Ne/N = 0.182) were estimated from the numbers of reproducing males and females. Ne estimates with genetic methods gave variable results. Our results verify and expand field data on reproduction by females and provide new data on reproduction by males and estimates of relatedness and Ne in a polar bear population.

  19. Genetic variation, relatedness, and effective population size of polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska.

    Science.gov (United States)

    Cronin, Matthew A; Amstrup, Steven C; Talbot, Sandra L; Sage, George K; Amstrup, Kristin S

    2009-01-01

    Polar bears (Ursus maritimus) are unique among bears in that they are adapted to the Arctic sea ice environment. Genetic data are useful for understanding their evolution and can contribute to management. We assessed parentage and relatedness of polar bears in the southern Beaufort Sea, Alaska, with genetic data and field observations of age, sex, and mother-offspring and sibling relationships. Genotypes at 14 microsatellite DNA loci for 226 bears indicate that genetic variation is comparable to other populations of polar bears with mean number of alleles per locus of 7.9 and observed and expected heterozygosity of 0.71. The genetic data verified 60 field-identified mother-offspring pairs and identified 10 additional mother-cub pairs and 48 father-offspring pairs. The entire sample of related and unrelated bears had a mean pairwise relatedness index (r(xy)) of approximately zero, parent-offspring and siblings had r(xy) of approximately 0.5, and 5.2% of the samples had r(xy) values within the range expected for parent-offspring. Effective population size (N(e) = 277) and the ratio of N(e) to total population size (N(e)/N = 0.182) were estimated from the numbers of reproducing males and females. N(e) estimates with genetic methods gave variable results. Our results verify and expand field data on reproduction by females and provide new data on reproduction by males and estimates of relatedness and N(e) in a polar bear population.

  20. P-wave velocity model of mud volcano on the continental slope of the Canadian Beaufort Sea from frequency-domain full waveform inversion

    Science.gov (United States)

    Jang, U. G.; Kang, S. G.; Hong, J. K.; Jin, Y. K.; Dallimore, S.; Riedel, M.; Paull, C. K.

    2017-12-01

    2014 Expedition ARA05C was a multidisciplinary undertaking conducted in the Canadian Beaufort Sea, Arctic Ocean on the Korean ice breaker IBRV ARAON from August 30 to September 19, 2014. The program was carried out as collaboration between the Korea Polar Research Institute (KOPRI), Geological Survey of Canada (GSC), Monterey Bay Aquarium Research Institute (MBARI), Department of Fisheries and Ocean (DFO) with participation by Bremen University (BARUM). During this expedition, multi-channel seismic (MCS) data were acquired on the outer continental shelf and upper slope of the Canadian Beaufort Sea, totaling 20 lines with 1,000 line-kilometers from September 1 to September 13, 2014. Three MCS survey lines was designed to cross the three submarine mud volcanoes found in the slope at approximate water depth of 290 m, 460 m and 740 m. Submarine mud volcanoes are seafloor structures with positive topography formed by a combination of mud eruption, gas emission, and water seepage from the subsurface. MCS data will allow image subsurface structures of mud volcanoes as identification of fluid migration pathways, however, imaging its subsurface structure is difficult by using conventional seismic data processing procedure, because it is seismically characterized by acoustically transparent facies. Full waveform inversion (FWI) is non-linear data-fitting procedure to estimate the physical properties of the subsurface by minimizing the difference between the observed and modelled data. FWI uses the two-wave wave equation to compute forward/backward wavefield to calculate the gradient direction, therefore it can derive more detailed velocity model beyond travel-time tomography techniques, which use only the kinematics of seismic data, by additional information provided by the amplitude and phase of the seismic waveform. In this study, we suggest P-wave structure of mud volcanos, which were inverted by 2D acoustic FWI. It will be useful to understand the characterization of mud

  1. Repeat AUV Mapping and ROV Observations of Active Mud Volcanos on the Canadian Beaufort Sea Continental Slope

    Science.gov (United States)

    Caress, D. W.; Paull, C. K.; Dallimore, S.; Lundsten, E. M.; Anderson, K.; Gwiazda, R.; Melling, H.; Lundsten, L.; Graves, D.; Thomas, H. J.; Cote, M.

    2017-12-01

    Two active submarine mud volcano sites located at 420 and 740 m depths on the margin of the Canadian Beaufort Sea were mapped in 2013 and again in 2016 using the same survey line pattern allowing detection of change over three years. The surveys were conducted using MBARI's mapping AUVs which fields a 200 kHz or 400 kHz multibeam sonar, a 1-6 kHz chirp sub-bottom profiler, and a 110 kHz chirp sidescan from a 50 m altitude. The resulting bathymetry has 1 m lateral resolution and 0.1 m vertical precision and sidescan mosaics have 1 m lateral resolution. Vertical changes of ≥0.2 m are observable by differencing repeat surveys. These features were also visited with MBARI's miniROV, which was outfitted for these dives with a manipulator mounted temperature probe. The 420 m mud volcano is nearly circular, 1100 m across, flat-topped, and superimposed on the pre-existing smooth slope. The central plateau has low relief ROV temperature probe inserted 2 cm into the flow measured 23°C, compared to ambient water (-0.4°C), indicating the rapid ascent of the mud from considerable subsurface depths. Bubbles (presumably methane) were escaping from the active mudflow. Combining seafloor mapping with ROV observations indicates that new sediment flows with entrained methane bubbles exhibit very high backscatter which rapidly changes to very low backscatter following degassing of the smooth, bare mud. To our knowledge this is the first time an eruption on a submarine mud volcano has been observed.

  2. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the LOUIS S. ST. LAURENT in the Arctic Ocean, Beaufort Sea and North Greenland Sea from 1994-07-24 to 1994-09-01 (NODC Accession 0113983)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113983 includes chemical, discrete sample, physical and profile data collected from LOUIS S. ST. LAURENT in the Arctic Ocean, Beaufort Sea and North...

  3. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from HEALY in the Arctic Ocean, Beaufort Sea and Bering Sea from 2004-07-18 to 2004-08-26 (NODC Accession 0115707)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0115707 includes biological, chemical, discrete sample, optical, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and...

  4. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, PAR Sensor and other instruments from the NATHANIEL B. PALMER in the Arctic Ocean, Beaufort Sea and Bering Sea from 2003-07-05 to 2003-08-20 (NODC Accession 0116064)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0116064 includes biological, chemical, discrete sample, physical and profile data collected from NATHANIEL B. PALMER in the Arctic Ocean, Beaufort Sea...

  5. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, PAR Sensor and other instruments from HEALY in the Arctic Ocean, Beaufort Sea and Bering Sea from 2004-05-15 to 2004-06-23 (NODC Accession 0115592)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0115592 includes biological, chemical, discrete sample, optical, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and...

  6. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, PAR Sensor and other instruments from HEALY in the Arctic Ocean, Beaufort Sea and Bering Sea from 2002-05-05 to 2002-06-15 (NODC Accession 0113952)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0113952 includes biological, chemical, discrete sample, optical, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and...

  7. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from HEALY in the Arctic Ocean, Beaufort Sea and Bering Sea from 2002-07-18 to 2002-08-21 (NODC Accession 0113953)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0113953 includes biological, chemical, discrete sample, physical and profile data collected from HEALY in the Arctic Ocean, Beaufort Sea and Bering...

  8. Food habits of Arctic staghorn sculpin (Gymnocanthus tricuspis) and shorthorn sculpin (Myoxocephalus scorpius) in the northeastern Chukchi and western Beaufort Seas

    Science.gov (United States)

    Gray, Benjamin P.; Norcross, Brenda L.; Beaudreau, Anne H.; Blanchard, Arny L.; Seitz, Andrew C.

    2017-01-01

    Arctic staghorn sculpin (Gymnocanthus tricuspis) and shorthorn sculpin (Myoxocephalus scorpius) belong to Cottidae, the second most abundant fish family in the western Arctic. Although considered important in food webs, little is known about their food habits throughout this region. To address this knowledge gap, we examined and compared the diets of 515 Arctic staghorn sculpin and 422 shorthorn sculpin using stomachs collected over three summers in the northeastern Chukchi Sea (2010-2012) and one summer in the western Beaufort Sea (2011). We used permutational multivariate analysis of variance (PERMANOVA) and non-metric multidimensional scaling (nMDS) to compare sculpin diets between regions and selected size classes. Differences in mouth morphologies and predator size versus prey size relationships were examined using regression techniques. Arctic staghorn sculpin and shorthorn sculpin diet compositions differed greatly throughout the Chukchi and Beaufort Seas. Regardless of body size, the smaller-mouthed Arctic staghorn sculpin consumed mostly benthic amphipods and polychaetes, whereas the larger-mouthed shorthorn sculpin shifted from a diet composed of benthic and pelagic macroinvertebrates as smaller individuals to shrimps and fish prey as larger individuals. Within shared habitats, the sculpins appear to partition prey, either by taxa or size, in a manner that suggests no substantial overlap occurs between species. This study increases knowledge of sculpin feeding ecology in the western Arctic and offers regional, quantitative diet information that could support current and future food web modeling efforts.

  9. An Analysis of the Beaufort Sea Thermohaline Structure and Variability, and Its Effects on Acoustic Propagation

    Science.gov (United States)

    2016-06-01

    Additionally, the canopy of the sea ice is not strictly flat and its variability in roughness and thickness can affect the absorption values of sound ...energy that interact with the surface. Therefore, depending on the surface properties , sound energy will experience variable attenuation, and...summer, is significant in respect to the degree they affect acoustic propagation. Thinning ice impacts the behavioral properties of sound energy in

  10. Atmospheric Profiles, Clouds, and the Evolution of Sea Ice Cover in the Beaufort and Chukchi Seas: Atmospheric Observations and Modeling as Part of the Seasonal Ice Zone Reconnaissance Surveys

    Science.gov (United States)

    2015-09-30

    project is an integrated observation and modeling program aimed at understanding the interplay of atmosphere, ice, and ocean in the SIZ of the Beaufort...Atmospheric Radiation Program (ARM) are utilized to validate instrumentation. Sea surface temperatures, ice concentrations, and floe size...clearly identifies the two cloud layers apparent in the ceilometer data. Note that the lower layer at about 400m is very thin and diffuse

  11. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from HEALY in the Arctic Ocean, Beaufort Sea and others from 2014-05-05 to 2014-08-30 (NCEI Accession 0144350)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144350 includes Surface underway data collected from HEALY in the Arctic Ocean, Beaufort Sea, Bering Sea, Coastal Waters of SE Alaska, Gulf of...

  12. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from HEALY in the Arctic Ocean, Beaufort Sea and others from 2013-08-06 to 2013-10-29 (NCEI Accession 0144346)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144346 includes Surface underway data collected from HEALY in the Arctic Ocean, Beaufort Sea, Bering Sea and Northwest Passage from 2013-08-06 to...

  13. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from HEALY in the Arctic Ocean, Beaufort Sea and others from 2015-07-14 to 2015-10-28 (NCEI Accession 0144530)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144530 includes Surface underway data collected from HEALY in the Arctic Ocean, Beaufort Sea, Bering Sea, Coastal Waters of SE Alaska, Gulf of Alaska...

  14. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from HEALY in the Arctic Ocean, Beaufort Sea and others from 2012-08-01 to 2012-10-24 (NCEI Accession 0144338)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144338 includes Surface underway data collected from HEALY in the Arctic Ocean, Beaufort Sea, Bering Sea, Coastal Waters of SE Alaska and North...

  15. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, Coulometer for DIC measurement and other instruments from the MIRAI in the Arctic Ocean, Beaufort Sea and others from 2002-08-22 to 2002-10-10 (NODC Accession 0112355)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0112355 includes biological, chemical, discrete sample, physical and profile data collected from MIRAI in the Arctic Ocean, Beaufort Sea, Bering Sea...

  16. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from HEALY in the Arctic Ocean, Beaufort Sea and others from 2011-05-27 to 2011-12-16 (NCEI Accession 0144345)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144345 includes Surface underway data collected from HEALY in the Arctic Ocean, Beaufort Sea, Bering Sea, Coastal Waters of SE Alaska, Gulf of...

  17. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from Marcus G. Langseth in the Arctic Ocean, Beaufort Sea and others from 2011-04-13 to 2011-12-28 (NCEI Accession 0144305)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0144305 includes Surface underway data collected from Marcus G. Langseth in the Arctic Ocean, Beaufort Sea, Bering Sea, Gulf of Alaska, Hawaiian...

  18. Collar temperature sensor data reveal long-term patterns in southern Beaufort Sea polar bear den distribution on pack ice and land

    Science.gov (United States)

    Olson, Jay W; Rode, Karyn D.; Eggett, Dennis L.; Smith, T.S.; Wilson, R. R.; Durner, George M.; Fischbach, Anthony; Atwood, Todd C.; Douglas, David

    2017-01-01

    In response to a changing climate, many species alter habitat use. Polar bears Ursus maritimus in the southern Beaufort Sea have increasingly used land for maternal denning. To aid in detecting denning behavior, we developed an objective method to identify polar bear denning events using temperature sensor data collected by satellite-linked transmitters deployed on adult females between 1985 and 2013. We then applied this method to determine whether southern Beaufort Sea polar bears have continued to increase land denning with recent sea-ice loss and examined whether sea-ice conditions affect the distribution of dens between pack-ice and coastal substrates. Because land use in summer and autumn has also increased, we examined potential associations between summering substrate and denning substrate. Statistical process control methods applied to temperature-sensor data identified denning events with 94.5% accuracy in comparison to direct observations (n = 73) and 95.7% accuracy relative to subjective classifications based on temperature, location, and activity sensor data (n = 116). We found an increase in land-based denning during the study period. The frequency of land denning was directly related to the distance that sea ice retreated from the coast. Among females that denned, all 14 that summered on land subsequently denned there, whereas 29% of the 69 bears summering on ice denned on land. These results suggest that denning on land may continue to increase with further loss of sea ice. While the effects that den substrate have on nutrition, energetics, and reproduction are unclear, more polar bears denning onshore will likely increase human-bear interactions.

  19. Multivariate benthic ecosystem functioning in the Arctic – benthic fluxes explained by environmental parameters in the southeastern Beaufort Sea

    Directory of Open Access Journals (Sweden)

    H. Link

    2013-09-01

    Full Text Available The effects of climate change on Arctic marine ecosystems and their biogeochemical cycles are difficult to predict given the complex physical, biological and chemical interactions among the ecosystem components. We studied benthic biogeochemical fluxes in the Arctic and the influence of short-term (seasonal to annual, long-term (annual to decadal and other environmental variability on their spatial distribution to provide a baseline for estimates of the impact of future changes. In summer 2009, we measured fluxes of dissolved oxygen, nitrate, nitrite, ammonia, soluble reactive phosphate and silicic acid at the sediment–water interface at eight sites in the southeastern Beaufort Sea at water depths from 45 to 580 m. The spatial pattern of the measured benthic boundary fluxes was heterogeneous. Multivariate analysis of flux data showed that no single or reduced combination of fluxes could explain the majority of spatial variation, indicating that oxygen flux is not representative of other nutrient sink–source dynamics. We tested the influence of eight environmental parameters on single benthic fluxes. Short-term environmental parameters (sinking flux of particulate organic carbon above the bottom, sediment surface Chl a were most important for explaining oxygen, ammonium and nitrate fluxes. Long-term parameters (porosity, surface manganese and iron concentration, bottom water oxygen concentrations together with δ13Corg signature explained most of the spatial variation in phosphate, nitrate and nitrite fluxes. Variation in pigments at the sediment surface was most important to explain variation in fluxes of silicic acid. In a model including all fluxes synchronously, the overall spatial distribution could be best explained (57% by the combination of sediment Chl a, phaeopigments, δ13Corg, surficial manganese and bottom water oxygen concentration. We conclude that it is necessary to consider long-term environmental variability along with

  20. Dissolved methane in the Beaufort Sea and the Arctic Ocean, 1992–2009; sources and atmospheric flux

    NARCIS (Netherlands)

    Lorenson, T.D.; Greinert, J.; Coffin, R.B.

    2016-01-01

    Methane concentration and isotopic composition was measured in ice-covered and ice-free waters of theArctic Ocean during 11 surveys spanning the years of 1992–1995 and 2009. During ice-free periods, methaneflux from the Beaufort shelf varies from 0.14 mg CH4 m22 d21 to 0.43 mg CH4 m22 d21. Maximum

  1. Beaufort Bridgenet Ichthyoplankton Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Beaufort Bridgenet Ichthyoplankton Sampling Program (BBISP) at the NOAA Beaufort facility is the longest consecutive ichthyoplankton ingress sampling program...

  2. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, Coulometer for DIC measurement and other instruments from the MIRAI in the Arctic Ocean and Beaufort Sea from 1999-09-11 to 1999-10-05 (NODC Accession 0112350)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0112350 includes chemical, discrete sample, physical and profile data collected from MIRAI in the Arctic Ocean and Beaufort Sea from 1999-09-11 to...

  3. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the LOUIS S. ST. LAURENT in the Arctic Ocean and Beaufort Sea from 1997-09-24 to 1997-10-15 (NODC Accession 0113984)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0113984 includes chemical, discrete sample, physical and profile data collected from LOUIS S. ST. LAURENT in the Arctic Ocean and Beaufort Sea from...

  4. Temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the TYRO in the Arctic Ocean and Beaufort Sea from 1996-09-13 to 1996-10-28 (NODC Accession 0116717)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0116717 includes chemical, discrete sample, physical and profile data collected from TYRO in the Arctic Ocean and Beaufort Sea from 1996-09-13 to...

  5. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the LOUIS S. ST. LAURENT in the Beaufort Sea and Northwest Passage from 1997-08-31 to 1997-09-16 (NODC Accession 0116061)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0116061 includes chemical, discrete sample, physical and profile data collected from LOUIS S. ST. LAURENT in the Beaufort Sea and Northwest Passage...

  6. Alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, Coulometer for DIC measurement and other instruments from MIRAI in the Arctic Ocean and Beaufort Sea from 2004-09-01 to 2004-10-13 (NODC Accession 0112357)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0112357 includes biological, chemical, discrete sample, physical and profile data collected from MIRAI in the Arctic Ocean and Beaufort Sea from...

  7. Long-term patterns of benthic irradiance and kelp production in the central Beaufort sea reveal implications of warming for Arctic inner shelves

    Science.gov (United States)

    Bonsell, Christina; Dunton, Kenneth H.

    2018-03-01

    This study synthesizes a multidecadal dataset of annual growth of the Arctic endemic kelp Laminaria solidungula and corresponding measurements of in situ benthic irradiance from Stefansson Sound in the central Beaufort Sea. We incorporate long-term data on sea ice concentration (National Sea Ice Data Center) and wind (National Weather Service) to assess how ice extent and summer wind dynamics affect the benthic light environment and annual kelp production. We find evidence of significant changes in sea ice extent in Stefansson Sound, with an extension of the ice-free season by approximately 17 days since 1979. Although kelp elongation at 5-7 m depths varies significantly among sites and years (3.8-49.8 cm yr-1), there is no evidence for increased production with either earlier ice break-up or a longer summer ice-free period. This is explained by very low light transmittance to the benthos during the summer season (mean daily percent surface irradiance ± SD: 1.7 ± 3.6 to 4.5 ± 6.6, depending on depth, with light attenuation values ranging from 0.5 to 0.8 m-1), resulting in minimal potential for kelp production on most days. Additionally, on month-long timescales (35 days) in the ice-free summer, benthic light levels are negatively related to wind speed. The frequent, wind-driven resuspension of sediments following ice break-up significantly reduce light to the seabed, effectively nullifying the benefits of an increased ice-free season on annual kelp growth. Instead, benthic light and primary production may depend substantially on the 1-3 week period surrounding ice break-up when intermediate sea ice concentrations reduce wind-driven sediment resuspension. These results suggest that both benthic and water column primary production along the inner shelf of Arctic marginal seas may decrease, not increase, with reductions in sea ice extent.

  8. Holocene dynamics in the Bering Strait inflow to the Arctic and the Beaufort Gyre circulation based on sedimentary records from the Chukchi Sea

    Directory of Open Access Journals (Sweden)

    M. Yamamoto

    2017-09-01

    Full Text Available The Beaufort Gyre (BG and the Bering Strait inflow (BSI are important elements of the Arctic Ocean circulation system and major controls on the distribution of Arctic sea ice. We report records of the quartz ∕ feldspar and chlorite ∕ illite ratios in three sediment cores from the northern Chukchi Sea, providing insights into the long-term dynamics of the BG circulation and the BSI during the Holocene. The quartz ∕ feldspar ratio, interpreted as a proxy of the BG strength, gradually decreased during the Holocene, suggesting a long-term decline in the BG strength, consistent with an orbitally controlled decrease in summer insolation. We propose that the BG rotation weakened as a result of the increasing stability of sea-ice cover at the margins of the Canada Basin, driven by decreasing insolation. Millennial to multi-centennial variability in the quartz ∕ feldspar ratio (the BG circulation is consistent with fluctuations in solar irradiance, suggesting that solar activity affected the BG strength on these timescales. The BSI approximation by the chlorite ∕ illite record, despite a considerable geographic variability, consistently shows intensified flow from the Bering Sea to the Arctic during the middle Holocene, which is attributed primarily to the effect of higher atmospheric pressure over the Aleutian Basin. The intensified BSI was associated with decrease in sea-ice concentrations and increase in marine production, as indicated by biomarker concentrations, suggesting a major influence of the BSI on sea-ice and biological conditions in the Chukchi Sea. Multi-century to millennial fluctuations, presumably controlled by solar activity, were also identified in a proxy-based BSI record characterized by the highest age resolution.

  9. Holocene dynamics in the Bering Strait inflow to the Arctic and the Beaufort Gyre circulation based on sedimentary records from the Chukchi Sea

    Science.gov (United States)

    Yamamoto, Masanobu; Nam, Seung-Il; Polyak, Leonid; Kobayashi, Daisuke; Suzuki, Kenta; Irino, Tomohisa; Shimada, Koji

    2017-09-01

    The Beaufort Gyre (BG) and the Bering Strait inflow (BSI) are important elements of the Arctic Ocean circulation system and major controls on the distribution of Arctic sea ice. We report records of the quartz / feldspar and chlorite / illite ratios in three sediment cores from the northern Chukchi Sea, providing insights into the long-term dynamics of the BG circulation and the BSI during the Holocene. The quartz / feldspar ratio, interpreted as a proxy of the BG strength, gradually decreased during the Holocene, suggesting a long-term decline in the BG strength, consistent with an orbitally controlled decrease in summer insolation. We propose that the BG rotation weakened as a result of the increasing stability of sea-ice cover at the margins of the Canada Basin, driven by decreasing insolation. Millennial to multi-centennial variability in the quartz / feldspar ratio (the BG circulation) is consistent with fluctuations in solar irradiance, suggesting that solar activity affected the BG strength on these timescales. The BSI approximation by the chlorite / illite record, despite a considerable geographic variability, consistently shows intensified flow from the Bering Sea to the Arctic during the middle Holocene, which is attributed primarily to the effect of higher atmospheric pressure over the Aleutian Basin. The intensified BSI was associated with decrease in sea-ice concentrations and increase in marine production, as indicated by biomarker concentrations, suggesting a major influence of the BSI on sea-ice and biological conditions in the Chukchi Sea. Multi-century to millennial fluctuations, presumably controlled by solar activity, were also identified in a proxy-based BSI record characterized by the highest age resolution.

  10. 75 FR 61094 - Drawbridge Operation Regulation; Atlantic Intracoastal Waterway, Beaufort, SC

    Science.gov (United States)

    2010-10-04

    .... Highway 21, Sea Island Parkway Bridge at mile marker 536 over the Beaufort River (Atlantic Intracoastal... Bridge, which is across the Atlantic Intracoastal Waterway at mile 539.0 in Port Royal, South Carolina... Bridge, across the Beaufort River, Mile 536.0 at Beaufort. The draw shall operate as follows: (1) On...

  11. The distribution and timing of bearded seal (Erignathus barbatus) vocalizations reflect changing environmental conditions in the Bering, Chukchi, and Beaufort Seas

    Science.gov (United States)

    MacIntyre, Kalyn Quintin

    The Arctic is experiencing dramatic shifts in climate that have led to changes in sea ice distribution, extent, and timing that pose adaptability challenges for Arctic species. Ice obligate species, such as the bearded seal, Erignathus barbatus, are inherently vulnerable to Arctic warming due to their reliance on seasonal sea ice as a platform for pupping and molting. Bearded seals are a highly vocal pan-Arctic species, in which males produce underwater vocal displays as part of courtship behavior during mating season. Bearded seal vocalizations were once believed to be a spring phenomenon, but results of this study have revealed year-round acoustic activity by bearded seals in the Bering, Chukchi, and Beaufort Seas (BCB). This new insight suggests that passive acoustic monitoring can be employed as an effective method to examine bearded seal distribution, migration patterns, and population structure year-round. This study provides a more complete understanding of bearded seal behavior and ecology through the analysis of year-round passive acoustic data collected in the BCB between 2008 and 2011. The BCB comprises three ecologically distinct bodies of water connected by the currents that flow northward from the Pacific Ocean through the Bering Strait and into the Arctic. The fine- and broad-scale oceanographic and physiographic variability that exists among the BCB may directly or indirectly (through sea ice conditions) affect bearded seal distributions. Analysis of seal vocal presence relative to sea ice distribution helped to clarify the relationships between bearded seal vocal behavior, habitat preferences and sea ice conditions. Regional and recording-site variability in call activity was largely related to sea ice conditions and geography, however oceanographic variability may contribute to the fine-scale variability in call activity that was present between closely located sites. This research provides a contemporary baseline of bearded seal distributions

  12. Long-term changes of mercury levels in ringed seal (Phoca hispida) from Amundsen Gulf, and beluga (Delphinapterus leucas) from the Beaufort Sea, western Canadian Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Outridge, P.M., E-mail: outridge@nrcan.gc.ca [Geological Survey of Canada, Natural Resources Canada, 601 Booth Street, Ottawa, Canada K1A 0E8 (Canada); Hobson, K.A. [Environment Canada, 11 Innovation Boulevard, Saskatoon, Canada S7N 3H5 (Canada); Savelle, J. [Department of Anthropology, McGill University, 855 Sherbrooke Street, Montreal, Canada H3A 2T7 (Canada)

    2009-11-15

    Mercury (Hg) concentrations were determined in the canine teeth of ringed seals (Phoca hispida) harvested during the 13th-14th, late 19th and early 21st Centuries in Amundsen Gulf, Northwest Territories, Canada. Most historical and pre-industrial teeth contained undetectable Hg levels (i.e. < 1.0 ng/g DW), whereas samples from 2001-03 contained up to 12 ng/g DW in an age-dependent pattern. Assuming a median [Hg] value in 13th-14th Century teeth of half the detection limit (i.e. 0.5 ng/g DW), geometric means of Hg in modern teeth were 9-17 times those of seals in the 14th Century, equivalent to an anthropogenic input of 89-94% of total Hg in modern seals. These results corroborate a previous study of beluga (Delphinapterus leucas) in the nearby Beaufort Sea. While the seals' trophic position (inferred from {delta}{sup 15}N values) did not change over time, modern {delta}{sup 13}C values were lower by about 2 per mille than in the 14th and 19th Centuries. This could be due to increased dissolution of anthropogenically derived CO{sub 2} in the ocean from the atmosphere, but could also indicate more offshore pelagic feeding by modern seals, which might be a factor in their Hg exposure. New tooth [Hg] data are also presented for the Beaufort Sea beluga, using recently-discovered museum samples collected in 1960/61, which showed that most of the anthropogenic contribution to beluga Hg had already taken effect by 1960 (reaching {approx} 75% of total Hg). Taken together, the long-term seal and beluga data indicate that whereas Hg levels in the marine ecosystems of the western Canadian Arctic were probably unchanged from pre-industrial times up to the late 19th Century, there was a significant, many-fold increase in the early to mid-20th Century, but little or no change after about the early 1960s.

  13. Sulfate reduction and methane oxidation activity below the sulfate-methane transition zone in Alaskan Beaufort Sea continental margin sediments: Implications for deep sulfur cycling

    Science.gov (United States)

    Treude, Tina; Krause, Stefan; Maltby, Johanna; Dale, Andrew W.; Coffin, Richard; Hamdan, Leila J.

    2014-11-01

    Two ∼6 m long sediment cores were collected along the ∼300 m isobath on the Alaskan Beaufort Sea continental margin. Both cores showed distinct sulfate-methane transition zones (SMTZ) at 105 and 120 cm below seafloor (cmbsf). Sulfate was not completely depleted below the SMTZ but remained between 30 and 500 μM. Sulfate reduction and anaerobic oxidation of methane (AOM) determined by radiotracer incubations were active throughout the methanogenic zone. Although a mass balance could not explain the source of sulfate below the SMTZ, geochemical profiles and correlation network analyses of biotic and abiotic data suggest a cryptic sulfur cycle involving iron, manganese and barite. Inhibition experiments with molybdate and 2-bromoethanesulfonate (BES) indicated decoupling of sulfate reduction and AOM and competition between sulfate reducers and methanogens for substrates. While correlation network analyses predicted coupling of AOM to iron reduction, the addition of manganese or iron did not stimulate AOM. Since none of the classical archaeal anaerobic methanotrophs (ANME) were abundant, the involvement of unknown or unconventional phylotypes in AOM is conceivable. The resistance of AOM activity to inhibitors implies deviation from conventional enzymatic pathways. This work suggests that the classical redox cascade of electron acceptor utilization based on Gibbs energy yields does not always hold in diffusion-dominated systems, and instead biotic processes may be more strongly coupled to mineralogy.

  14. Long-term changes of mercury levels in ringed seal (Phoca hispida) from Amundsen Gulf, and beluga (Delphinapterus leucas) from the Beaufort Sea, western Canadian Arctic

    International Nuclear Information System (INIS)

    Outridge, P.M.; Hobson, K.A.; Savelle, J.

    2009-01-01

    Mercury (Hg) concentrations were determined in the canine teeth of ringed seals (Phoca hispida) harvested during the 13th-14th, late 19th and early 21st Centuries in Amundsen Gulf, Northwest Territories, Canada. Most historical and pre-industrial teeth contained undetectable Hg levels (i.e. 15 N values) did not change over time, modern δ 13 C values were lower by about 2 per mille than in the 14th and 19th Centuries. This could be due to increased dissolution of anthropogenically derived CO 2 in the ocean from the atmosphere, but could also indicate more offshore pelagic feeding by modern seals, which might be a factor in their Hg exposure. New tooth [Hg] data are also presented for the Beaufort Sea beluga, using recently-discovered museum samples collected in 1960/61, which showed that most of the anthropogenic contribution to beluga Hg had already taken effect by 1960 (reaching ∼ 75% of total Hg). Taken together, the long-term seal and beluga data indicate that whereas Hg levels in the marine ecosystems of the western Canadian Arctic were probably unchanged from pre-industrial times up to the late 19th Century, there was a significant, many-fold increase in the early to mid-20th Century, but little or no change after about the early 1960s.

  15. Carbon sources in suspended particles and surface sediments from the Beaufort Sea revealed by molecular lipid biomarkers and compound-specific isotope analysis

    Directory of Open Access Journals (Sweden)

    I. Tolosa

    2013-03-01

    Full Text Available Molecular lipid biomarkers (hydrocarbons, alcohols, sterols and fatty acids and compound-specific isotope analysis of suspended particulate organic matter (SPM and surface sediments of the Mackenzie Shelf and slope (southeast Beaufort Sea, Arctic Ocean were studied in summer 2009. The concentrations of the molecular lipid markers, characteristic of known organic matter sources, were grouped and used as proxies to evaluate the relative importance of fresh algal, detrital algal, fossil, C3 terrestrial plants, bacterial and zooplankton material in the organic matter (OM of this area. Fossil and detrital algal contributions were the major fractions of the freshwater SPM from the Mackenzie River with ~34% each of the total molecular biomarkers. Fresh algal, C3 terrestrial, bacterial and zooplanktonic components represented much lower percentages, 17, 10, 4 and 80%, with a minor contribution of fossil and C3 terrestrial biomarkers. Characterization of the sediments revealed a major sink of refractory algal material mixed with some fresh algal material, fossil hydrocarbons and a small input of C3 terrestrial sources. In particular, the sediments from the shelf and at the mouth of the Amundsen Gulf presented the highest contribution of detrital algal material (60–75%, whereas those from the slope contained the highest proportion of fossil (40% and C3 terrestrial plant material (10%. Overall, considering that the detrital algal material is marine derived, autochthonous sources contributed more than allochthonous sources to the OM lipid pool. Using the ratio of an allochthonous biomarker (normalized to total organic carbon, TOC found in the sediments to those measured at the river mouth water, we estimated that the fraction of terrestrial material preserved in the sediments accounted for 30–40% of the total carbon in the inner shelf sediments, 17% in the outer shelf and Amundsen Gulf and up to 25% in the slope sediments. These estimates are low

  16. Wind and Wave Influences on Sea Ice Floe Size and Leads in the Beaufort and Chukchi Seas During the Summer-Fall Transition 2014

    Science.gov (United States)

    2016-01-26

    www.apl.washington.edu/project/project. php?id5arctic_sea_state). Making use of the available data related to these field programs, we perform a much smaller scope...consisting of subpixel- sized floes in a mixture of cakes , brash, and water that occurs between larger floes. Manual correction to trace out the floe...thresholds are interpolated into all regions [Chow and Kaneko, 1972]. Then the pointwise interpolation is applied to make sure each point has its thresh

  17. Estimating absorption coefficients of colored dissolved organic matter (CDOM using a semi-analytical algorithm for southern Beaufort Sea waters: application to deriving concentrations of dissolved organic carbon from space

    Directory of Open Access Journals (Sweden)

    A. Matsuoka

    2013-02-01

    Full Text Available A series of papers have suggested that freshwater discharge, including a large amount of dissolved organic matter (DOM, has increased since the middle of the 20th century. In this study, a semi-analytical algorithm for estimating light absorption coefficients of the colored fraction of DOM (CDOM was developed for southern Beaufort Sea waters using remote sensing reflectance at six wavelengths in the visible spectral domain corresponding to MODIS ocean color sensor. This algorithm allows the separation of colored detrital matter (CDM into CDOM and non-algal particles (NAP through the determination of NAP absorption using an empirical relationship between NAP absorption and particle backscattering coefficients. Evaluation using independent datasets, which were not used for developing the algorithm, showed that CDOM absorption can be estimated accurately to within an uncertainty of 35% and 50% for oceanic and coastal waters, respectively. A previous paper (Matsuoka et al., 2012 showed that dissolved organic carbon (DOC concentrations were tightly correlated with CDOM absorption in our study area (r2 = 0.97. By combining the CDOM absorption algorithm together with the DOC versus CDOM relationship, it is now possible to estimate DOC concentrations in the near-surface layer of the southern Beaufort Sea using satellite ocean color data. DOC concentrations in the surface waters were estimated using MODIS ocean color data, and the estimates showed reasonable values compared to in situ measurements. We propose a routine and near real-time method for deriving DOC concentrations from space, which may open the way to an estimate of DOC budgets for Arctic coastal waters.

  18. Supplementary Measurements in the Beaufort/Chukchi 2015 MIZ

    Science.gov (United States)

    2015-09-30

    Emerging Dynamics Of The Marginal Ice Zone DRI allowed us to autonomously examine one year’s evolution of the lower atmosphere, sea ice and upper-ocean...within the Beaufort/ Chukchi Sea marginal ice zone (MIZ). It is both advantageous and scientifically valid to continue this monitoring effort and...severed. IMB incorporated in ridge…. Dead Even though the system only survived a limited period of time it provided significant information on the

  19. Beaufort West, South Africa

    African Journals Online (AJOL)

    2011-02-16

    Feb 16, 2011 ... The Abrahamskraal formation represents a highly-sinuous fluvial environment, and was deposited predominantly by overbank flooding from meandering rivers flowing across an extensive alluvial plain towards the receding Ecca Sea. The overlying Teekloof formation differs from the Abrahamskraal.

  20. Morbillivirus and Toxoplasma exposure and association with hematological parameters for southern Beaufort Sea polar bears: potential response to infectious agents in a sentinel species.

    Science.gov (United States)

    Kirk, Cassandra M; Amstrup, Steven; Swor, Rhonda; Holcomb, Darce; O'Hara, Todd M

    2010-09-01

    Arctic temperatures are increasing in response to greenhouse gas forcing and polar bears have already responded to changing conditions. Declines in body stature and vital rates have been linked to warming-induced loss of sea-ice. As food webs change and human activities respond to a milder Arctic, exposure of polar bears and other arctic marine organisms to infectious agents may increase. Because of the polar bear's status as arctic ecosystem sentinel, polar bear health could provide an index of changing pathogen occurrence throughout the Arctic, however, exposure and monitoring protocols have yet to be established. We examine prevalence of antibodies to Toxoplasma gondii, and four morbilliviruses (canine distemper [CDV], phocine distemper [PDV], dolphin morbillivirus [DMV], porpoise morbillivirus [PMV]) including risk factors for exposure. We also examine the relationships between antibody levels and hematologic values established in the previous companion article. Antibodies to Toxoplasma gondii and morbilliviruses were found in both sample years. We found a significant inverse relationship between CDV titer and total leukocytes, neutrophils, monocytes, and eosinophils, and a significant positive relationship between eosinophils and Toxoplasma gondii antibodies. Morbilliviral prevalence varied significantly among age cohorts, with 1-2 year olds least likely to be seropositive and bears aged 5-7 most likely. Data suggest that the presence of CDV and Toxoplasma gondii antibodies is associated with polar bear hematologic values. We conclude that exposure to CDV-like antigen is not randomly distributed among age classes and suggest that differing behaviors among life history stages may drive probability of specific antibody presence.

  1. Morbillivirus and Toxoplasma exposure and association with hematological parameters for southern Beaufort Sea polar bears: potential response to infectious agents in a sentinel species

    Science.gov (United States)

    Kirk, Cassandra M.; Amstrup, Steven C.; Swor, Rhonda; Holcomb, Darce; O'Hara, Todd M.

    2010-01-01

    Arctic temperatures are increasing in response to greenhouse gas forcing and polar bears have already responded to changing conditions. Declines in body stature and vital rates have been linked to warming-induced loss of sea-ice. As food webs change and human activities respond to a milder Arctic, exposure of polar bears and other arctic marine organisms to infectious agents may increase. Because of the polar bear’s status as arctic ecosystem sentinel, polar bear health could provide an index of changing pathogen occurrence throughout the Arctic, however, exposure and monitoring protocols have yet to be established. We examine prevalence of antibodies to Toxoplasma gondii, and four morbilliviruses (canine distemper [CDV], phocine distemper [PDV], dolphin morbillivirus [DMV], porpoise morbillivirus [PMV]) including risk factors for exposure. We also examine the relationships between antibody levels and hematologic values established in the previous companion article. Antibodies to Toxoplasma gondii and morbilliviruses were found in both sample years. We found a significant inverse relationship between CDV titer and total leukocytes, neutrophils, monocytes, and eosinophils, and a significant positive relationship between eosinophils and Toxoplasma gondii antibodies. Morbilliviral prevalence varied significantly among age cohorts, with 1–2 year olds least likely to be seropositive and bears aged 5–7 most likely. Data suggest that the presence of CDV and Toxoplasma gondii antibodies is associated with polar bear hematologic values. We conclude that exposure to CDV-like antigen is not randomly distributed among age classes and suggest that differing behaviors among life history stages may drive probability of specific antibody presence.

  2. Beaufort Gyre hydrographic data: Temperature, salinity and transmissivity data from the Louis S St. Laurent in the Arctic Ocean, 2003 - 2008 (NODC Accession 0058268)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The major goal of the observational program is to determine the variability of different components of the Beaufort Gyre fresh water (ocean and sea ice) system and...

  3. Marine mammal observations collected using aircraft by ConocoPhillips in the Chukchi Sea, 1989-1991 and submitted as part of the ConocoPhillips and Shell Joint Monitoring Program in the Chukchi and Beaufort Seas (NODC Accession 0120533)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vessel- and aircraft-based marine mammal surveys in the Chukchi Sea collected from 1989 to 1991. The aerial marine mammal surveys were...

  4. Sea turtles sightings in North Carolina

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sea turtles sightings are reported to the NMFS Beaufort Laboratory sea turtle program by the general public as they are fishing, boating, etc. These sightings...

  5. Impact of environmental factors on the distribution of extreme scouring (gouging) event, Canadian Beaufort shelf

    Energy Technology Data Exchange (ETDEWEB)

    Blasco, Steve [Geological Survey of Canada, Dartmouth (Canada); Carr, Erin; Campbell, Patrick [Canadian Seabed Research Ltd., Porters Lake (Canada); Shearer, Jim [Shearer Consulting, Ottawa (Canada)

    2011-07-01

    A knowledge of the presence of scours, their dimensions and their return frequencies is highly important in the development of hydrocarbon offshore structures. Mapping surveys have identified 290 extreme scour events across the Canadian Beaufort shelf. This paper investigated the impact of environmental factors on the distribution of extreme scouring events in the Canadian Beaufort shelf. This study used the NEWBASE database of new ice scours to perform an analysis of the scours appearance mechanisms. The geotechnical zonation, the bathymetry and the shelf gradient were evaluated using these data. Estimation of the surficial sediment type, the surficial sediment thickness and sea ice regime were also made. It was found that the spatial distribution of extreme scour events is controlled by sea-ice regime, bathymetry and geotechnical zonation. The results obtained from mapping surveys suggested that the key controlling environmental factors may combine to limit the depth of extreme scour events to 5 meters.

  6. AFSC/REFM: Beaufort Sea Marine Fish Survey, Beaufort Sea, Alaska, August 2008, Fisheries Interaction Team

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Alaska Fisheries Science Center's Status of Stocks and Multispecies Assessment (SSMA) Programs Fishery Interaction Team (FIT) conducted a fish survey in the...

  7. Marine mammal observations collected by aircraft and ship and submitted as part of the ConocoPhillips and Shell Joint Monitoring Program in the Chukchi and Beaufort Seas, 2006-2007 (NODC Accession 0120531)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set was collected as part of the Joint Monitoring Program during seismic activities in the Chukchi Sea. The 2006 data was collected by ship and aircraft as...

  8. Surface currents and temperature data from satellite-tracked drifters in the Chukchi and Beaufort Seas from 2011-08-07 to 2014-03-06 (NODC Accession 0126984)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Drifters were deployed from vessels in the Chukchi Sea during the ice-free seasons of 2011-2013. Drifter positions were determined via GPS, and positions were...

  9. Mineralogical, geochemical, and magnetic signatures of surface sediments from the Canadian Beaufort Shelf and Amundsen Gulf (Canadian Arctic)

    Science.gov (United States)

    Gamboa, Adriana; Montero-Serrano, Jean-Carlos; St-Onge, Guillaume; Rochon, André; Desiage, Pierre-Arnaud

    2017-02-01

    Mineralogical, geochemical, magnetic, and siliciclastic grain-size signatures of 34 surface sediment samples from the Mackenzie-Beaufort Sea Slope and Amundsen Gulf were studied in order to better constrain the redox status, detrital particle provenance, and sediment dynamics in the western Canadian Arctic. Redox-sensitive elements (Mn, Fe, V, Cr, Zn) indicate that modern sedimentary deposition within the Mackenzie-Beaufort Sea Slope and Amundsen Gulf took place under oxic bottom-water conditions, with more turbulent mixing conditions and thus a well-oxygenated water column prevailing within the Amundsen Gulf. The analytical data obtained, combined with multivariate statistical (notably, principal component and fuzzy c-means clustering analyses) and spatial analyses, allowed the division of the study area into four provinces with distinct sedimentary compositions: (1) the Mackenzie Trough-Canadian Beaufort Shelf with high phyllosilicate-Fe oxide-magnetite and Al-K-Ti-Fe-Cr-V-Zn-P contents; (2) Southwestern Banks Island, characterized by high dolomite-K-feldspar and Ca-Mg-LOI contents; (3) the Central Amundsen Gulf, a transitional zone typified by intermediate phyllosilicate-magnetite-K-feldspar-dolomite and Al-K-Ti-Fe-Mn-V-Zn-Sr-Ca-Mg-LOI contents; and (4) mud volcanoes on the Canadian Beaufort Shelf distinguished by poorly sorted coarse-silt with high quartz-plagioclase-authigenic carbonate and Si-Zr contents, as well as high magnetic susceptibility. Our results also confirm that the present-day sedimentary dynamics on the Canadian Beaufort Shelf is mainly controlled by sediment supply from the Mackenzie River. Overall, these insights provide a basis for future studies using mineralogical, geochemical, and magnetic signatures of Canadian Arctic sediments in order to reconstruct past variations in sediment inputs and transport pathways related to late Quaternary climate and oceanographic changes.

  10. The exchange of inorganic carbon on the Canadian Beaufort Shelf

    Science.gov (United States)

    Mol, Jacoba; Thomas, Helmuth; Hu, Xianmin; Myers, Paul G.

    2017-04-01

    The Mackenzie Shelf in the southeastern Beaufort Sea is an area that has experienced large changes in the past several decades as warming, sea-ice loss, and increased river discharge have altered carbon cycling. Upwelling and downwelling events are common on the shelf, caused by strong, fluctuating along-shore winds and resulting cross-shelf Ekman transport. Downwelling carries inorganic carbon and other remineralization products off the shelf and into the deep basin for possible long-term storage in the world oceans. Upwelling carries water high in dissolved inorganic carbon (DIC) and nutrients from the Pacific-origin upper halocline layer (UHL) onto the shelf. Profiles of DIC and total alkalinity (TA) taken in August and September of 2014 are used to investigate the cycling of inorganic carbon on the Mackenzie Shelf. The along-shore and cross-shelf transport of inorganic carbon is quantified using velocity field output from a simulation of the Arctic and Northern Hemisphere Atlantic (ANHA4) configuration of the Nucleus of European Modelling of the Ocean (NEMO) model. A strong upwelling event prior to sampling on the Mackenzie Shelf is analyzed and the resulting influence on the carbonate system, including the saturation state of aragonite and pH levels, is investigated. TA and δ18O are used to examine water mass distributions in the study area and analyze the influence of Pacific Water, Mackenzie River freshwater, and sea-ice melt on carbon dynamics and air-sea fluxes of CO2 in the surface mixed layer. Understanding carbon transfer in this seasonally dynamic environment is key in order to quantify the importance of Arctic shelf regions to the global carbon cycle and to provide a basis for understanding how its role will respond to the aforementioned changes in the regional marine system.

  11. Sea turtles sightings in North Carolina from 1987-02-01 to 2015-06-16 (NCEI Accession 0161174)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data contains sea turtle sightings reported to the NMFS Beaufort Laboratory sea turtle program by the general public as they were fishing, boating, etc. These...

  12. Beaufort Sea Methane Hydrate Exploration: Energy and Climate Change

    Science.gov (United States)

    2011-05-27

    Branch Marine Geosciences Division i REPORT DOCUMENTATION PAGE Form ApprovedOMB No. 0704-0188 3. DATES COVERED (From - To) Standard Form 298 (Rev. 8...Geology and Petroleum Potential, Proceedings of the Norwegian Petroleum Society Conference, 15-17 August 1990, Tromsø, Norway. Norwegian Petroleum ...potential of individual gas hydrate accumulations in the Gulf of Mexico continental slope. Marine and Petroleum Geology 20: 111-128. Rothwell, R. G

  13. AIDJEX Beaufort Sea Upward Looking Sonar April 1976

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data contains Upward Looking Sonar (ULS) profiles of the underside of the Arctic pack ice along three transects whose total length is 777 nautical miles. The...

  14. Scaling Observations of Surface Waves in the Beaufort Sea

    Science.gov (United States)

    2016-04-14

    open water distances were estimated using the daily 4 km National Ice Center’s (NIC) Multisensor Snow and Ice Mapping System (IMS) product, which uses...MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S) Office of Naval Research ONR 875 North Randolph Street ...drifting buoys during the 2014 open water season, are interpreted using open water distances determined from satellite ice products and wind forcing time

  15. AIDJEX Beaufort Sea Upward Looking Sonar April 1976, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data contains Upward Looking Sonar (ULS) profiles of the underside of the Arctic pack ice along three transects whose total length is 777 nautical miles. The...

  16. Determining volume sensitive waters in Beaufort County, SC tidal creeks

    Science.gov (United States)

    Andrew Tweel; Denise Sanger; Anne Blair; John Leffler

    2016-01-01

    Non-point source pollution from stormwater runoff associated with large-scale land use changes threatens the integrity of ecologically and economically valuable estuarine ecosystems. Beaufort County, SC implemented volume-based stormwater regulations on the rationale that if volume discharge is controlled, contaminant loading will also be controlled.

  17. New sedimentological evidence supporting a catastrophic meltwater discharge event along the Beaufort margin, Arctic Ocean

    Science.gov (United States)

    Klotsko, S.; Driscoll, N. W.; Keigwin, L. D.; Mendenhall, B.

    2015-12-01

    In 2013, a cruise on the USCGC Healy mapped the Beaufort margin from Barrow, AK into the Amundsen Gulf using a towed CHIRP subbottom profiler and a hull-mounted Knudsen CHIRP subbottom profiler to study the deglaciation of the margin. Sediment cores were also acquired. New grain size analyses for three sediment cores will be presented. These records help constrain the flooding events captured in the existing grain size data from JPC 15, just east of the Mackenzie trough. This core shows evidence of multiple ice rafted debris events that were likely sourced from the retreat of the Amundsen ice stream. These layers have peaks in grain size around ~20 microns compared to the ~5 micron average for the rest of the core. The grain size peaks correlate to the high amplitude reflectors observed in the seismic CHIRP data. Similar reflectors are observed in the seismic data from two of the new core locations, one in the Mackenzie trough and one east of the trough. The seismic data from these stations also record a thick sediment package that is ~7 meters thick at its depocenter. This layer is interpreted to record a massive meltwater discharge event that entered the Arctic via the Mackenzie River. Oxygen isotope data from JPC 15 support an event at this location based on the covarying benthic and planktonic records. In our conceptual model, the pulses of freshwater from the Amundsen Gulf likely freshened the margin sufficiently that the major discharge event was then able to push the system over the edge. This catastrophic glacial lake draining out the Mackenzie River into the Beaufort Sea and export out of the Arctic into the North Atlantic caused diminished meridional overturning circulation - slowing of the conveyor belt thermohaline circulation - which, in turn, potentially caused the Younger Dryas cold period.

  18. Optimizing Observations of Sea Ice Thickness and Snow Depth in the Arctic

    Science.gov (United States)

    2015-09-30

    high proportion of multi-year ice (MYI), such as north of Greenland and Ellesmere Island. Over much of the Beaufort Sea, Canada Basin and central ...2015), Perspectives: Remote Sensing of Snow on Sea Ice, Snow on Sea Ice Processes Workshop, National Center for Atmospheric Research – Mesa Lab

  19. Decadal shifts in autumn migration timing by Pacific Arctic beluga whales are related to delayed annual sea ice formation.

    Science.gov (United States)

    Hauser, Donna D W; Laidre, Kristin L; Stafford, Kathleen M; Stern, Harry L; Suydam, Robert S; Richard, Pierre R

    2017-06-01

    Migrations are often influenced by seasonal environmental gradients that are increasingly being altered by climate change. The consequences of rapid changes in Arctic sea ice have the potential to affect migrations of a number of marine species whose timing is temporally matched to seasonal sea ice cover. This topic has not been investigated for Pacific Arctic beluga whales (Delphinapterus leucas) that follow matrilineally maintained autumn migrations in the waters around Alaska and Russia. For the sympatric Eastern Chukchi Sea ('Chukchi') and Eastern Beaufort Sea ('Beaufort') beluga populations, we examined changes in autumn migration timing as related to delayed regional sea ice freeze-up since the 1990s, using two independent data sources (satellite telemetry data and passive acoustics) for both populations. We compared dates of migration between 'early' (1993-2002) and 'late' (2004-2012) tagging periods. During the late tagging period, Chukchi belugas had significantly delayed migrations (by 2 to >4 weeks, depending on location) from the Beaufort and Chukchi seas. Spatial analyses also revealed that departure from Beaufort Sea foraging regions by Chukchi whales was postponed in the late period. Chukchi beluga autumn migration timing occurred significantly later as regional sea ice freeze-up timing became later in the Beaufort, Chukchi, and Bering seas. In contrast, Beaufort belugas did not shift migration timing between periods, nor was migration timing related to freeze-up timing, other than for southward migration at the Bering Strait. Passive acoustic data from 2008 to 2014 provided independent and supplementary support for delayed migration from the Beaufort Sea (4 day yr -1 ) by Chukchi belugas. Here, we report the first phenological study examining beluga whale migrations within the context of their rapidly transforming Pacific Arctic ecosystem, suggesting flexible responses that may enable their persistence yet also complicate predictions of how

  20. Implementation of a Personnel Management System "Beaufort": Successes and failures at a Dutch Hospital

    NARCIS (Netherlands)

    Bondarouk, Tatiana; Khosrow-Pour, M.

    2004-01-01

    This case describes a project concerning the implementation of a personnel management system - Beaufort - in Medinet, one of the larger regional general hospitals in The Netherlands. The project plan included two sequential phases: firstly, the introduction of Beaufort to the central personnel and

  1. Contemporary Arctic Sea Level

    Science.gov (United States)

    Cazenave, A. A.

    2017-12-01

    During recent decades, the Arctic region has warmed at a rate about twice the rest of the globe. Sea ice melting is increasing and the Greenland ice sheet is losing mass at an accelerated rate. Arctic warming, decrease in the sea ice cover and fresh water input to the Arctic ocean may eventually impact the Arctic sea level. In this presentation, we review our current knowledge of contemporary Arctic sea level changes. Until the beginning of the 1990s, Arctic sea level variations were essentially deduced from tide gauges located along the Russian and Norwegian coastlines. Since then, high inclination satellite altimetry missions have allowed measuring sea level over a large portion of the Arctic Ocean (up to 80 degree north). Measuring sea level in the Arctic by satellite altimetry is challenging because the presence of sea ice cover limits the full capacity of this technique. However adapted processing of raw altimetric measurements significantly increases the number of valid data, hence the data coverage, from which regional sea level variations can be extracted. Over the altimetry era, positive trend patterns are observed over the Beaufort Gyre and along the east coast of Greenland, while negative trends are reported along the Siberian shelf. On average over the Arctic region covered by satellite altimetry, the rate of sea level rise since 1992 is slightly less than the global mea sea level rate (of about 3 mm per year). On the other hand, the interannual variability is quite significant. Space gravimetry data from the GRACE mission and ocean reanalyses provide information on the mass and steric contributions to sea level, hence on the sea level budget. Budget studies show that regional sea level trends over the Beaufort Gyre and along the eastern coast of Greenland, are essentially due to salinity changes. However, in terms of regional average, the net steric component contributes little to the observed sea level trend. The sea level budget in the Arctic

  2. Diversity, abundance and community structure of benthic macro- and megafauna on the Beaufort shelf and slope.

    Science.gov (United States)

    Nephin, Jessica; Juniper, S Kim; Archambault, Philippe

    2014-01-01

    Diversity and community patterns of macro- and megafauna were compared on the Canadian Beaufort shelf and slope. Faunal sampling collected 247 taxa from 48 stations with box core and trawl gear over the summers of 2009-2011 between 50 and 1,000 m in depth. Of the 80 macrofaunal and 167 megafaunal taxa, 23% were uniques, present at only one station. Rare taxa were found to increase proportional to total taxa richness and differ between the shelf (megafauna principally comprised echinoderms with Ophiocten sp. (up to 90% in relative abundance/station) dominant on the shelf and Ophiopleura sp. dominant on the slope. Macro- and megafauna had divergent patterns of abundance, taxa richness (α diversity) and β diversity. A greater degree of macrofaunal than megafaunal variation in abundance, richness and β diversity was explained by confounding factors: location (east-west), sampling year and the timing of sampling with respect to sea-ice conditions. Change in megafaunal abundance, richness and β diversity was greatest across the depth gradient, with total abundance and richness elevated on the shelf compared to the slope. We conclude that megafaunal slope taxa were differentiated from shelf taxa, as faunal replacement not nestedness appears to be the main driver of megafaunal β diversity across the depth gradient.

  3. Emerging Trends in the Sea State of the Beaufort and Chukchi Seas

    Science.gov (United States)

    2016-07-06

    also feedbacks between waves and ice formation, such as the rapid freezing that occurs when waves cause pan- cake ice to develop ( Wadhams et al...sizes make differences statistically insignificant). Fig. 9 shows normalized histograms of peak wave period nd fitted probability distribution

  4. Final Scientific/Technical Report of Gas Hydrate Dynamics on the Alaskan Beaufort Continental Slope: Modeling and Field Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Hornbach, Matthew J [Southern Methodist Univ., Dallas, TX (United States); Colwell, Frederick S [Oregon State Univ., Corvallis, OR (United States); Harris, Robert [Oregon State Univ., Corvallis, OR (United States)

    2017-07-06

    Methane Hydrates, a solid form of methane and water, exist at high pressures and low temperatures, occurs on every continental margin on Earth, represents one of the largest reservoirs of carbon on the planet, and, if destabilized, may play an important role in both slope stability and climate change. For decades, researchers have studied methane hydrates with the hope of determining if methane hydrates are destabilizing, and if so, how this destabilization might impact slope stability and ocean/atmosphere carbon budgets. In the past ~5 years, it has become well established that the upper “feather-edge” of methane hydrate stability (intermediate water depths of ~200-500 meters below sea level) represents an important frontier for methane hydrates stability research, as this zone is most susceptible to destabilization due to minor fluctuations in ocean temperature in space and time. The Arctic Ocean—one of the fastest warming regions on Earth—is perhaps the best place to study possible changes to methane hydrate stability due to ocean warming. To address the stability of methane hydrates at intermediate ocean depths, Southern Methodist University in partnership with Oregon State University and The United State Geological Survey at Woods Hole began investigating methane hydrate stability in intermediate water depths below both the US Beaufort Sea and the Atlantic Margin, from 2012-2017. The work was funded by the Department of Energy’s (DOE) National Energy Technology Laboratory (NETL). The key goal of the SMU component of this study was to collect the first ever heat flow data in the Beaufort Sea and compare measured shallow (probe-based1) heat flow values with deeper (BSR-derived2) heat flow values, and from this, determine whether hydrates were in thermal equilibrium. In September 2016, SMU/OSU collected the first ever heat flow measurements in the US Beaufort Sea. Despite poor weather and rough seas, the cruise was a success, with 116 heat flow

  5. Ecological characteristics of core-use areas used by Bering-Chukchi-Beaufort (BCB) bowhead whales, 2006-2012

    Science.gov (United States)

    Citta, John J.; Quakenbush, Lori T.; Okkonen, Stephen R.; Druckenmiller, Matthew L.; Maslowski, Wieslaw; Clement-Kinney, Jaclyn; George, John C.; Brower, Harry; Small, Robert J.; Ashjian, Carin J.; Harwood, Lois A.; Heide-Jørgensen, Mads Peter

    2015-08-01

    The Bering-Chukchi-Beaufort (BCB) population of bowhead whales (Balaena mysticetus) ranges across the seasonally ice-covered waters of the Bering, Chukchi, and Beaufort seas. We used locations from 54 bowhead whales, obtained by satellite telemetry between 2006 and 2012, to define areas of concentrated use, termed "core-use areas". We identified six primary core-use areas and describe the timing of use and physical characteristics (oceanography, sea ice, and winds) associated with these areas. In spring, most whales migrated from wintering grounds in the Bering Sea to the Cape Bathurst polynya, Canada (Area 1), and spent the most time in the vicinity of the halocline at depths <75 m, which are within the euphotic zone, where calanoid copepods ascend following winter diapause. Peak use of the polynya occurred between 7 May and 5 July; whales generally left in July, when copepods are expected to descend to deeper depths. Between 12 July and 25 September, most tagged whales were located in shallow shelf waters adjacent to the Tuktoyaktuk Peninsula, Canada (Area 2), where wind-driven upwelling promotes the concentration of calanoid copepods. Between 22 August and 2 November, whales also congregated near Point Barrow, Alaska (Area 3), where east winds promote upwelling that moves zooplankton onto the Beaufort shelf, and subsequent relaxation of these winds promoted zooplankton aggregations. Between 27 October and 8 January, whales congregated along the northern shore of Chukotka, Russia (Area 4), where zooplankton likely concentrated along a coastal front between the southeastward-flowing Siberian Coastal Current and northward-flowing Bering Sea waters. The two remaining core-use areas occurred in the Bering Sea: Anadyr Strait (Area 5), where peak use occurred between 29 November and 20 April, and the Gulf of Anadyr (Area 6), where peak use occurred between 4 December and 1 April; both areas exhibited highly fractured sea ice. Whales near the Gulf of Anadyr spent almost

  6. Evidence for radionuclide transport by sea ice

    International Nuclear Information System (INIS)

    Meese, D.A.; Tucker, W.B.; Gow, A.J.; Reimnitz, E.; Bischof, J.; Darby, D.

    1997-01-01

    Ice and ice-borne sediments were collected across the Arctic Basin during the Arctic Ocean Section, 1994 (AOS-94), a recent US/Canada trans-Arctic expedition. Sediments were analysed for 137 Cs, clay mineralogy and carbon. Concentrations of 137 Cs ranged from 5 to 73 Bq kg -1 in the ice-borne sediments. Concentrations of ice samples without sediment were all less than 1 Bq m -3 . The sediment sample with the highest 137 Cs concentration (73 Bq kg -1 ) was collected in the Beaufort Sea. This concentration was significantly higher than in bottom sediments collected in the same area, indicating an ice transport mechanism from an area with correspondingly higher concentrations. Recent results from the application of ice transport models and sediment analyses indicate that it is very likely that sediments are transported by ice, from the Siberian shelf areas to the Beaufort Sea

  7. MITAS-2009 Expedition, U.S. Beaufort Shelf and Slope—Lithostratigraphy Data Report

    Energy Technology Data Exchange (ETDEWEB)

    Rose, K.; Johnson, J.E.; Phillips, S.C.; Smith, J.; Reed, A.; Disenhof, C.; Presley, J.

    2012-09-17

    The volume of methane released through the Arctic Ocean to the atmosphere and its potential role in the global climate cycle have increasingly become the focus of studies seeking to understand the source and origin of this methane. In 2009, an international, multi-disciplinary science party aboard the U.S. Coast Guard icebreaker Polar Sea successfully completed a trans-U.S. Beaufort Shelf expedition aimed at understanding the sources and volumes of methane across this region. Following more than a year of preliminary cruise planning and a thorough site evaluation, the Methane in the Arctic Shelf/Slope (MITAS) expedition departed from the waters off the coast of Barrow, Alaska in September 2009. The expedition was organized with an international shipboard science team consisting of 33 scientists with the breadth of expertise necessary to meet the expedition goals. NETL researchers led the expedition’s initial core processing and lithostratigraphic evaluations, which are the focus of this report. This data report is focused on the lithostratigraphic datasets from the recovered vibra cores and piston cores. Operational information about the piston and vibra cores such as date acquired, core name, total length, water depth, and geographic location is provided. Once recovered, gas samples were immediately collected from cores. In addition, each core was run through the Geotek multi-sensor core logger for magnetic susceptibility, P-wave velocity, resistivity, and gamma-density measurements (Rose et al., 2010). After the samples and measurements were completed, the cores were split into working and archive halves. Visual core descriptions of the archive half was completed for each core. Samples for shipboard smear slides, coarse fractions, and XRD analyses were collected, as well as corresponding samples for post-cruise grain size analysis from the working half of each core. Line scan images of the split core surfaces were collected post-expedition. The methods used to

  8. Diversity, abundance and community structure of benthic macro- and megafauna on the Beaufort shelf and slope.

    Directory of Open Access Journals (Sweden)

    Jessica Nephin

    Full Text Available Diversity and community patterns of macro- and megafauna were compared on the Canadian Beaufort shelf and slope. Faunal sampling collected 247 taxa from 48 stations with box core and trawl gear over the summers of 2009-2011 between 50 and 1,000 m in depth. Of the 80 macrofaunal and 167 megafaunal taxa, 23% were uniques, present at only one station. Rare taxa were found to increase proportional to total taxa richness and differ between the shelf (< 100 m where they tended to be sparse and the slope where they were relatively abundant. The macrofauna principally comprised polychaetes with nephtyid polychaetes dominant on the shelf and maldanid polychaetes (up to 92% in relative abundance/station dominant on the slope. The megafauna principally comprised echinoderms with Ophiocten sp. (up to 90% in relative abundance/station dominant on the shelf and Ophiopleura sp. dominant on the slope. Macro- and megafauna had divergent patterns of abundance, taxa richness (α diversity and β diversity. A greater degree of macrofaunal than megafaunal variation in abundance, richness and β diversity was explained by confounding factors: location (east-west, sampling year and the timing of sampling with respect to sea-ice conditions. Change in megafaunal abundance, richness and β diversity was greatest across the depth gradient, with total abundance and richness elevated on the shelf compared to the slope. We conclude that megafaunal slope taxa were differentiated from shelf taxa, as faunal replacement not nestedness appears to be the main driver of megafaunal β diversity across the depth gradient.

  9. De Beaufort, een aanzienlijke familie tijdens de Republiek, de Bataafs-Franse tijd en het Koninkrijk 1613-1876

    NARCIS (Netherlands)

    Melchers, R.R.J.

    2014-01-01

    In 1613 Pierre de Beaufort aged 18, left the French town of Sedan for the Dutch Republic. At his death in 1661 in Hulst he had become a man of distinction. More than 200 years later on 30 May 1868 his direct descendant Pieter de Beaufort received from the Hoge Raad van Adel (High Court of Nobility)

  10. There goes the sea ice: following Arctic sea ice parcels and their properties.

    Science.gov (United States)

    Tschudi, M. A.; Tooth, M.; Meier, W.; Stewart, S.

    2017-12-01

    Arctic sea ice distribution has changed considerably over the last couple of decades. Sea ice extent record minimums have been observed in recent years, the distribution of ice age now heavily favors younger ice, and sea ice is likely thinning. This new state of the Arctic sea ice cover has several impacts, including effects on marine life, feedback on the warming of the ocean and atmosphere, and on the future evolution of the ice pack. The shift in the state of the ice cover, from a pack dominated by older ice, to the current state of a pack with mostly young ice, impacts specific properties of the ice pack, and consequently the pack's response to the changing Arctic climate. For example, younger ice typically contains more numerous melt ponds during the melt season, resulting in a lower albedo. First-year ice is typically thinner and more fragile than multi-year ice, making it more susceptible to dynamic and thermodynamic forcing. To investigate the response of the ice pack to climate forcing during summertime melt, we have developed a database that tracks individual Arctic sea ice parcels along with associated properties as these parcels advect during the summer. Our database tracks parcels in the Beaufort Sea, from 1985 - present, along with variables such as ice surface temperature, albedo, ice concentration, and convergence. We are using this database to deduce how these thousands of tracked parcels fare during summer melt, i.e. what fraction of the parcels advect through the Beaufort, and what fraction melts out? The tracked variables describe the thermodynamic and dynamic forcing on these parcels during their journey. This database will also be made available to all interested investigators, after it is published in the near future. The attached image shows the ice surface temperature of all parcels (right) that advected through the Beaufort Sea region (left) in 2014.

  11. The Arctic sea ice biological communities in recent environmental changes (scientific note)

    OpenAIRE

    Melnikov,Igor A.; Zhitina,Ludmila S.; Kolosova,Helena G.

    2001-01-01

    Biological materials obtained at the former Soviet Union ice station "North Pole-22" (NP-22) within the Beaufort Gyre in 1975-1981 have shown that the multi-year ice and ice-water interface is a rich and diverse environment inhabited by large numbers of diatoms and invertebrates. Recent data from the ice camp SHEBA (Surface Heat Budget of the Arctic Ocean) from the Beaufort Gyre in 1997-1998,comparable to the NP-22 data, demonstrate the following changes : (i) populations of sea ice diatoms a...

  12. Models of talik, permafrost and gas hydrate histories - Beaufort Mackenzie Basin, Canada

    Czech Academy of Sciences Publication Activity Database

    Majorowicz, J.; Osadetz, K.; Šafanda, Jan

    2015-01-01

    Roč. 8, č. 7 (2015), s. 6738-6764 ISSN 1996-1073 Institutional support: RVO:67985530 Keywords : gas hydrates * permafrost * Beaufort-Mackenzie Basin * taliks Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.077, year: 2015

  13. Final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project. Appendix K (continued)

    International Nuclear Information System (INIS)

    1999-02-01

    BP Exploration (Alaska) Inc. (BPXA) submitted a permit application to the US Army Engineer District, Alaska to initiate the review process for BPXA's plans to develop and produce oil and gas from the Northstar Unit. This report contains Appendices K (continued) of an Environmental Impact Statement which was undertaken to identify and evaluate the potential effects the proposed project may have on the environment

  14. BIVALVE BIOGEOGRAPHIC DISTRIBUTIONS, ABUNDANCES, AND CLIMATE VULNERABILITY FROM THE BEAUFORT SEA TO THE GULF OF CALIFORNIA

    Science.gov (United States)

    As part of an U.S. EPA/USGS project to predict the relative vulnerability of near-coastal species to climate change along the Pacific Coast, we have synthesized the biogeographic distributions and abundances of bivalves found in depths <200 m. We have included the twelve &ldqu...

  15. EMBATTLED BIVALVES: BIOGEOGRAPHIC DISTRIBUTIONS AND ABUNDANCES FROM THE BEAUFORT SEA TO THE GULF OF CALIFORNIA

    Science.gov (United States)

    As part of an EPA/USGS project to predict the relative vulnerability of near-coastal species to climate change, we have synthesized in a web-based tool, the Coastal Biogeographic Risk Analysis Tool (CBRAT), the biogeographic distributions and abundances of bivalves, found in dept...

  16. 77 FR 10707 - Safety Zone; NOBLE DISCOVERER, Outer Continental Shelf Drillship, Chukchi and Beaufort Seas, Alaska

    Science.gov (United States)

    2012-02-23

    ... (or signing the comment, if submitted on behalf of an association, business, labor union, etc.). You... environment given the sensitivity of the environmental and subsistence importance to the indigenous population...

  17. 75 FR 18404 - Safety Zone; FRONTIER DISCOVERER, Outer Continental Shelf Drillship, Chukchi and Beaufort Sea...

    Science.gov (United States)

    2010-04-12

    ... safety zone could consist of large commercial shipping vessels, fishing vessels, cruise ships, tugs with... State or local governments and would either preempt State law or impose a substantial direct cost of... standards would be inconsistent with applicable law or otherwise impractical. Voluntary consensus standards...

  18. 75 FR 803 - Safety Zone; FRONTIER DISCOVERER, Outer Continental Shelf Drillship, Chukchi and Beaufort Sea...

    Science.gov (United States)

    2010-01-06

    ... commercial shipping vessels, fishing vessels, cruise ships, tugs with tows and the occasional recreational... governments and would either preempt State law or impose a substantial direct cost of compliance on them. We... explanation of why using these standards would be inconsistent with applicable law or otherwise impractical...

  19. Knowledge-based sea ice classification by polarimetric SAR

    DEFF Research Database (Denmark)

    Skriver, Henning; Dierking, Wolfgang

    2004-01-01

    Polarimetric SAR images acquired at C- and L-band over sea ice in the Greenland Sea, Baltic Sea, and Beaufort Sea have been analysed with respect to their potential for ice type classification. The polarimetric data were gathered by the Danish EMISAR and the US AIRSAR which both are airborne...... systems. A hierarchical classification scheme was chosen for sea ice because our knowledge about magnitudes, variations, and dependences of sea ice signatures can be directly considered. The optimal sequence of classification rules and the rules themselves depend on the ice conditions/regimes. The use...... of the polarimetric phase information improves the classification only in the case of thin ice types but is not necessary for thicker ice (above about 30 cm thickness)...

  20. Cs-137 in the Savannah River and the Beaufort-Jasper and Port Wentworth water-treatment plants

    International Nuclear Information System (INIS)

    Hayes, D.W.; Boni, A.L.

    1983-01-01

    Cesium-137 concentration measurements made in 1965 are reported for the Savannah River above and below the Savannah River Plant (SRP) and for the Beaufort-Jasper and Port Wentworth water treatment plants down river. These concentrations, measured when four SRP reactors (C, K, L, and P) were operating, were used to estimate Cs-137 reduction ratios for transport in the Savannah River and across each water treatment plant. In 1965 there was a 48% reduction in the Cs-137 concentration in the Savannah River between Highway 301 and the water treatment plant inlet points. Measured Cs-137 values in the finished water from Port Wentworth and the Beaufort-Jasper water treatment plants showed an 80% and 98% reduction in concentration level, respectively, when compared to Cs-137 concentration at Highway 301. The lower Cs-137 concentration (0.04 pCi/l) in the Beaufort-Jasper finished water is attributed to dilution in the canal from inflow of surface water (40%) and sediment cleanup processes that take place in the open portions of the canal (about 17 to 18 miles). Using the 1965 data, maximum Cs-137 concentrations expected in finished water in the Beaufort-Jasper and Port Wentworth water treatment plants following L-Reactor startup were recalculated. The recalculated values are 0.01 and 0.09 pCi/l for Beaufort-Jasper and Port Wentworth, respectively, compared to the 1.05 pCi/l value in the Environmental Assessment

  1. Circulation, Cross-Shelf Exchange, Sea Ice, and Marine Mammal Habitats on the Alaska Beaufort Sea Shelf

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — HLY 13-03 was a familiar mission that continued our efforts from HLY 12-03, beginning and ending in Dutch Harbor, AK. Throughout the mission we remained primarily in...

  2. Environment of deposition and stratigraphy of the uranium-bearing strata around Beaufort West, South Africa

    International Nuclear Information System (INIS)

    Horowitz, A.

    1976-04-01

    Palynological analyses of some 50 samples collected from uranium-bearing strata - as well as the layers immediately above and below them - around Beaufort West, South Africa, indicate that these sediments were laid down in a wide, rather shallow delta in Late Permian times. Most of the sediments are fluvio-deltaic, and most of the plant remains were transported from the north, the hinterland in those times. A considerable percentage of the microfossils, e.g. Veryhachium and hystrichospheres, are clearly from a marine environment. The occurrence of marine microfossils in the spectrum, as compared with those of terrestrial provenance, increases considerably southwards [af

  3. Inferred gas hydrate and permafrost stability history models linked to climate change in the Beaufort-Mackenzie Basin, Arctic Canada

    Czech Academy of Sciences Publication Activity Database

    Majorowicz, J.; Šafanda, Jan; Osadetz, K.

    2012-01-01

    Roč. 8, č. 2 (2012), s. 667-682 ISSN 1814-9324 Institutional research plan: CEZ:AV0Z30120515 Institutional support: RVO:67985530 Keywords : climate change * Beaufort-Mackenzie Basin * permafrost Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 3.556, year: 2012

  4. Sea State and Boundary Layer Physics in the Emerging Arctic Ocean

    Science.gov (United States)

    Thomson, J. M.

    2016-12-01

    The sea state of the Arctic Ocean is changing. With an increasing retreat of sea ice in the summer months, storms are now more likely to occur over open water, and the result is an increasing trend in both the heights and periods of surface waves in the Chukchi and Beaufort Seas. The elevated sea state affects, in turn, the refreezing process in the autumn. In 2015, a field campaign collected a comprehensive suite of air-ice-ocean measurements during the autumn freeze-up in the Beaufort Sea, and these measurements are used to investigate the surface wave effects and coupled dynamics. The most prominent process is the formation of pancake ice, which occurs when surface wave motions disturb newly forming frazil ice. Analysis of a wave event from open water through different stages of a gradually maturing pancake ice cover shows high sensitivity of the surface waves to the types of ice cover. Other cases suggest that waves impact the near-surface heat flux convergence, impacting the ice formation. Hence, there is a two-way interaction between ice and waves. Wave attenuation is captured with adjustment of a viscoelastic parameterization in a wave hindcast model. The results suggest that a fully coupled air-ice-wave model will be necessary to describe the evolution of sea state and ice cover during the Arctic freeze-up.

  5. Characterizing Arctic Sea Ice Topography Using High-Resolution IceBridge Data

    Science.gov (United States)

    Petty, Alek; Tsamados, Michel; Kurtz, Nathan; Farrell, Sinead; Newman, Thomas; Harbeck, Jeremy; Feltham, Daniel; Richter-Menge, Jackie

    2016-01-01

    We present an analysis of Arctic sea ice topography using high resolution, three-dimensional, surface elevation data from the Airborne Topographic Mapper, flown as part of NASA's Operation IceBridge mission. Surface features in the sea ice cover are detected using a newly developed surface feature picking algorithm. We derive information regarding the height, volume and geometry of surface features from 2009-2014 within the Beaufort/Chukchi and Central Arctic regions. The results are delineated by ice type to estimate the topographic variability across first-year and multi-year ice regimes.

  6. Recent Arctic Sea Level Variations from Satellites

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Piccioni, Gaia

    2016-01-01

    Sea level monitoring in the Arctic region has always been an extreme challenge for remote sensing, and in particular for satellite altimetry. Despite more than two decades of observations, altimetry is still limited in the inner Arctic Ocean. We have developed an updated version of the Danish...... Technical University's (DTU) Arctic Ocean altimetric sea level timeseries starting in 1993 and now extended up to 2015 with CryoSat-2 data. The time-series covers a total of 23 years, which allows higher accuracy in sea level trend determination. The record shows a sea level trend of 2.2 ± 1.1 mm....../y for the region between 66°N and 82°N. In particular, a local increase of 15 mm/y is found in correspondence to the Beaufort Gyre. An early estimate of the mean sea level trend budget closure in the Arctic for the period 2005–2015 was derived by using the Equivalent Water Heights obtained from GRACE Tellus...

  7. Late Holocene sea ice conditions in Herald Canyon, Chukchi Sea

    Science.gov (United States)

    Pearce, C.; O'Regan, M.; Rattray, J. E.; Hutchinson, D. K.; Cronin, T. M.; Gemery, L.; Barrientos, N.; Coxall, H.; Smittenberg, R.; Semiletov, I. P.; Jakobsson, M.

    2017-12-01

    Sea ice in the Arctic Ocean has been in steady decline in recent decades and, based on satellite data, the retreat is most pronounced in the Chukchi and Beaufort seas. Historical observations suggest that the recent changes were unprecedented during the last 150 years, but for a longer time perspective, we rely on the geological record. For this study, we analyzed sediment samples from two piston cores from Herald Canyon in the Chukchi Sea, collected during the 2014 SWERUS-C3 Arctic Ocean Expedition. The Herald Canyon is a local depression across the Chukchi Shelf, and acts as one of the main pathways for Pacific Water to the Arctic Ocean after entering through the narrow and shallow Bering Strait. The study site lies at the modern-day seasonal sea ice minimum edge, and is thus an ideal location for the reconstruction of past sea ice variability. Both sediment cores contain late Holocene deposits characterized by high sediment accumulation rates (100-300 cm/kyr). Core 2-PC1 from the shallow canyon flank (57 m water depth) is 8 meter long and extends back to 4200 cal yrs BP, while the upper 3 meters of Core 4-PC1 from the central canyon (120 mwd) cover the last 3000 years. The chronologies of the cores are based on radiocarbon dates and the 3.6 ka Aniakchak CFE II tephra, which is used as an absolute age marker to calculate the marine radiocarbon reservoir age. Analysis of biomarkers for sea ice and surface water productivity indicate stable sea ice conditions throughout the entire late Holocene, ending with an abrupt increase of phytoplankton sterols in the very top of both sediment sequences. The shift is accompanied by a sudden increase in coarse sediments (> 125 µm) and a minor change in δ13Corg. We interpret this transition in the top sediments as a community turnover in primary producers from sea ice to open water biota. Most importantly, our results indicate that the ongoing rapid ice retreat in the Chukchi Sea of recent decades was unprecedented during the

  8. Recent Changes in Arctic Sea Ice Melt Onset, Freeze-Up, and Melt Season Length

    Science.gov (United States)

    Markus, Thorsten; Stroeve, Julienne C.; Miller, Jeffrey

    2010-01-01

    In order to explore changes and trends in the timing of Arctic sea ice melt onset and freeze-up and therefore melt season length, we developed a method that obtains this information directly from satellite passive microwave data, creating a consistent data set from 1979 through present. We furthermore distinguish between early melt (the first day of the year when melt is detected) and the first day of continuous melt. A similar distinction is made for the freeze-up. Using this method we analyze trends in melt onset and freeze-up for 10 different Arctic regions. In all regions except for the Sea of Okhotsk, which shows a very slight and statistically insignificant positive trend (O.4 days/decade), trends in melt onset are negative, i.e. towards earlier melt. The trends range from -1.0day/decade for the Bering Sea to -7.3 days/decade for the East Greenland Sea. Except for the Sea of Okhotsk all areas also show a trend towards later autumn freeze onset. The Chukchi/Beaufort Seas and Laptev/East Siberian Seas observe the strongest trends with 7 days/decade. For the entire Arctic, the melt season length has increased by about 20 days over the last 30 years. Largest trends of over 1O days/decade are seen for Hudson Bay, the East Greenland Sea the Laptev/East Siberian Seas, and the Chukchi/Beaufort Seas. Those trends are statistically significant a1 the 99% level.

  9. Degradation state of organic matter in surface sediments from the Beaufort Shelf: a lipid approach

    Science.gov (United States)

    Rontani, J.-F.; Charriere, B.; Petit, M.; Vaultier, F.; Heipieper, H. J.; Link, H.; Chaillou, G.; Sempéré, R.

    2012-03-01

    The lipid content of surface sediments collected on the Beaufort Shelf was examined. Particular attention was given to biotic and abiotic degradation products of sterols and monounsaturated fatty acids. By using sitosterol and campesterol degradation products as tracers of the degradation of terrestrial higher plant inputs and brassicasterol degradation products as tracers of degradation of phytoplanktonic organisms, it could be observed that autoxidation, photooxidation and biodegradation processes act much more intensively on higher plant debris than on phytoplanktonic organisms. Examination of oxidation products of monounsaturated fatty acids showed that photo- and autoxidation processes act more intensively on bacteria than on phytodetritus. Enhanced damages induced by singlet oxygen (transferred from senescent phytoplanktonic cells) in bacteria were attributed to the lack of an adapted antioxidant system in these microorganisms. The strong oxidative stress observed in the sampled sediments resulted in the production of significant amounts of epoxyacids and unusually very high proportions of monounsaturated fatty acids with a trans double bond. The formation of epoxyacids was attributed to peroxygenases (enzymes playing a protective role against the deleterious effects of fatty acid hydroperoxides in vivo), while cis/trans isomerization was probably induced by thiyl radicals produced during the reaction of thiols with hydroperoxides. Our results confirm the important role played by abiotic oxidative processes in the degradation of marine bacteria and do not support the generally expected refractory character of terrigenous material deposited in deltaic systems.

  10. Coastal erosion and mass wasting along the Canadian Beaufort Sea based on annual airborne LiDAR elevation data

    Science.gov (United States)

    Obu, Jaroslav; Lantuit, Hugues; Grosse, Guido; Günther, Frank; Sachs, Torsten; Helm, Veit; Fritz, Michael

    2017-09-01

    Erosion of permafrost coasts has received increasing scientific attention since 1990s because of rapid land loss and the mobilisation potential of old organic carbon. The majority of permafrost coastal erosion studies are limited to time periods from a few years to decades. Most of these studies emphasize the spatial variability of coastal erosion, but the intensity of inter-annual variations, including intermediate coastal aggradation, remains poorly documented. We used repeat airborne Light Detection And Ranging (LiDAR) elevation data from 2012 and 2013 with 1 m horizontal resolution to study coastal erosion and accompanying mass-wasting processes in the hinterland. Study sites were selected to include different morphologies along the coast of the Yukon Coastal Plain and on Herschel Island. We studied elevation and volume changes and coastline movement and compared the results between geomorphic units. Results showed simple uniform coastal erosion from low coasts (up to 10 m height) and a highly diverse erosion pattern along coasts with higher backshore elevation. This variability was particularly pronounced in the case of active retrogressive thaw slumps, which can decrease coastal erosion or even cause temporary progradation by sediment release. Most of the extremes were recorded in study sites with active slumping (e.g. 22 m of coastline retreat and 42 m of coastline progradation). Coastline progradation also resulted from the accumulation of slope collapse material. These occasional events can significantly affect the coastline position on a specific date and can affect coastal retreat rates as estimated in long term by coastline digitalisation from air photos and satellite imagery. These deficiencies can be overcome by short-term airborne LiDAR measurements, which provide detailed and high-resolution information about quickly changing elevations in coastal areas.

  11. Ocean drifter studies of surface currents along the coasts of Newfoundland and Labrador and in the Beaufort Sea

    National Research Council Canada - National Science Library

    Diemand, D; Reimer, Ernest M; Barrie, J. Vaughn

    1982-01-01

    .... Some passed through the Bering Strait and were found in the Aleutian Islands and the were coast of North America, however most, predictably, were swept westward from the release sites and were found along the north and west coasts of Alaska and the N.W.T.

  12. Final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project. Volume 3: Chapters 5 through 7

    International Nuclear Information System (INIS)

    1999-02-01

    BP Exploration (Alaska) Inc. (BPXA) submitted a permit application to the US Army Engineer District, Alaska to initiate the review process for BPXA's plans to develop and produce oil and gas from the Northstar Unit. This report contains chapters 5--7 of an Environmental Impact Statement which was undertaken to identify and evaluate the potential effects the proposed project may have on the environment. Attention is focused on the effects of oil on the physical, biological, and human environments

  13. Final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project. Volume 4: Chapters 8 through 13

    International Nuclear Information System (INIS)

    1999-02-01

    BP Exploration (Alaska) Inc. (BPXA) submitted a permit application to the US Army Engineer District, Alaska to initiate the review process for BPXA's plans to develop and produce oil and gas from the Northstar Unit. This report contains chapters 8--13 of an Environmental Impact Statement which was undertaken to identify and evaluate the potential effects the proposed project may have on the environment. Attention is focused on the following: effects of oil on the physical, biological, and human environments; effects of noise on the biological and human environments; cumulative effects on the environment; and comparison of project alternatives and their impacts

  14. Final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project. Appendices B through K

    International Nuclear Information System (INIS)

    1999-02-01

    BP Exploration (Alaska) Inc. (BPXA) submitted a permit application to the US. Army Engineer District, Alaska to initiate the review process for BPXA's plans to develop and produce oil and gas from the Northstar Unit. This report contains Appendices B--K of an Environmental Impact Statement which was undertaken to identify and evaluate the potential effects the proposed project may have on the environment

  15. AFSC/NMML: Marine Mammal Aerial Surveys in the Bering, Chukchi and Beaufort Seas . 1979-2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Bureau of Ocean Energy Management (BOEM), formerly the Minerals Management Service (MMS), and its precursor, the Bureau of Land Management, have funded aerial...

  16. AFSC/NMML: Bowhead Whale Feeding Ecology Study (BOWFEST): Aerial Survey in Chukchi and Beaufort Seas, 2007-2011

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Bowhead Whale Feeding Ecology Study (BOWFEST) was initiated in May 2007 through an Interagency Agreement between the Bureau of Ocean Energy Management (BOEM)...

  17. 77 FR 38718 - Safety Zone; NOBLE DISCOVERER, Outer Continental Shelf Drillship, Chukchi and/or Beaufort Seas, AK

    Science.gov (United States)

    2012-06-29

    ... Guard understands that the underlying justifications for the safety zone are not likely to change from...-30), U.S. Department of Transportation, West Building Ground Floor, Room W12-140, 1200 New Jersey... reinforced for ice resistance. The NOBLE DISCOVERER has a ``persons on board'' capacity of 124, and it is...

  18. Final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project. Volume 2: Chapters 1 through 4

    International Nuclear Information System (INIS)

    1999-02-01

    BP Exploration (Alaska) Inc. (BPXA) submitted a permit application to the US Army Engineer District, Alaska (Corps) to initiate the review process for BPXA's plans to develop and produce oil and gas from the Northstar Unit. The Corps determined that issuance of a permit for BPXA's proposed project constituted a major federal action that may significant affect the quality of the human environment pursuant to the National Environmental Policy Act (NEPA). In addition, the US Environmental Protection Agency (EPA), upon review of BPXA's permit application, determined under provisions of the Clean Water Act and 40 CFR Part 6 Subpart F that permitting for BPXA's proposed project constituted a major federal action that may significantly affect the quality of the human environment. As a result, preparation of an Environmental Impact Statement (EIS) under NEPA was undertaken to identify and evaluate a range of reasonable alternatives and evaluate the potential effects the alternatives, including BPXA's proposed project, may have on the human environment

  19. Bottom Sediment Granulometric Data for the Continental Margins of the Bering, Chukchi, East Siberia, Laptev, and Beaufort Seas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are part of Roberts, Richard W., University of Washington, Department of Oceanography Special Report No. 70, Bottom Sediment Granulometric Data for the...

  20. Final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project. Volume 1: Executive summary

    International Nuclear Information System (INIS)

    1999-02-01

    BP Exploration (Alaska) Inc. (BPXA) submitted a permit application to comply with Section 404 of the Clean Water Act and Section 10 of the Rivers and Harbors Act to the US Army Engineer District, Alaska (Corps). The application initiated the review process for BPXA's proposed project to develop and produce oil and gas from the Northstar Unit. The National Environmental Policy Act (NEPA) requires preparation of an Environmental Impact Statement (EIS) prior to any federal action that may significantly affect the quality of the human environment. The EIS is intended to provide federal agencies with information about the consequences of a proposed project and to disclose that information to the public, soliciting their comments, prior to the agencies making decisions on the project

  1. Final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project. Appendices L through P

    International Nuclear Information System (INIS)

    1999-02-01

    BP Exploration (Alaska) Inc. (BPXA) submitted a permit application to the US Army Engineer District, Alaska to initiate the review process for BPXA's plans to develop and produce oil and gas from the Northstar Unit. This report contains Appendices L-P of an Environmental Impact Statement which was undertaken to identify and evaluate the potential effects the proposed project may have on the environment

  2. 77 FR 39164 - Safety Zone; KULLUK, Outer Continental Shelf Mobile Offshore Drilling Unit (MODU), Beaufort Sea, AK

    Science.gov (United States)

    2012-07-02

    ... zone could consist of large commercial shipping vessels, fishing vessels, cruise ships, tugs with tows... authority for state or local law enforcement officers to make arrests for safety zones established under the... Outer Continental Shelf Lands Act and 33 C.F.R 147. Accordingly, State and Local law enforcement...

  3. 77 FR 10711 - Safety Zone; KULLUK, Outer Continental Shelf Mobile Offshore Drilling Unit (MODU), Beaufort Sea, AK

    Science.gov (United States)

    2012-02-23

    ... vessels, cruise ships, tugs with tows and the occasional recreational vessel. For any group intending to... State or local governments and would either preempt State law or impose a substantial direct cost of... standards would be inconsistent with applicable law or otherwise impractical. Voluntary consensus standards...

  4. Evaluation of four structural best management practices for highway runoff in Beaufort and Colleton Counties, South Carolina, 2005–2006

    Science.gov (United States)

    Conlon, Kevin J.; Journey, Celeste

    2008-01-01

    From 2005 to 2006, the U.S. Geological Survey worked cooperatively with the South Carolina Department of Transportation in Beaufort and Colleton Counties, South Carolina, to assess the performance of four different structural devices that served as best management practices (BMPs). These structural devices were installed to mitigate the effects of stormwater runoff on waterways near State roads. The South Carolina Department of Transportation is required to address the quality of stormwater runoff from State-maintained roadways as part of the National Pollutant Discharge Elimination System stormwater program mandated in the Clean Water Act.

  5. Influence of sea ice on Arctic coasts

    Science.gov (United States)

    Barnhart, K. R.; Kay, J. E.; Overeem, I.; Anderson, R. S.

    2017-12-01

    Coasts form the dynamic interface between the terrestrial and oceanic systems. In the Arctic, and in much of the world, the coast is a focal point for population, infrastructure, biodiversity, and ecosystem services. A key difference between Arctic and temperate coasts is the presence of sea ice. Changes in sea ice cover can influence the coast because (1) the length of the sea ice-free season controls the time over which nearshore water can interact with the land, and (2) the location of the sea ice edge controls the fetch over which storm winds can interact with open ocean water, which in turn governs nearshore water level and wave field. We first focus on the interaction of sea ice and ice-rich coasts. We combine satellite records of sea ice with a model for wind-driven storm surge and waves to estimate how changes in the sea ice-free season have impacted the nearshore hydrodynamic environment along Alaska's Beaufort Sea Coast for the period 1979-2012. This region has experienced some of the greatest changes in both sea ice cover and coastal erosion rates in the Arctic: the median length of the open-water season has expanded by 90 percent, while coastal erosion rates have more than doubled from 8.7 to 19 m yr-1. At Drew Point, NW winds increase shoreline water levels that control the incision of a submarine notch, the rate-limiting step of coastal retreat. The maximum water-level setup at Drew Point has increased consistently with increasing fetch. We extend our analysis to the entire Arctic using both satellite-based observations and global coupled climate model output from the Community Earth System Model Large Ensemble (CESM-LE) project. This 30-member ensemble employs a 1-degree version of the CESM-CAM5 historical forcing for the period 1920-2005, and RCP 8.5 forcing from 2005-2100. A control model run with constant pre-industrial (1850) forcing characterizes internal variability in a constant climate. Finally, we compare observations and model results to

  6. Temporal and spatial variability in sea-ice carbon:nitrogen ratios on Canadian Arctic shelves

    Directory of Open Access Journals (Sweden)

    Andrea Niemi

    2015-12-01

    Full Text Available Abstract To enhance the accuracy of carbon cycling models as applied to sea ice in the changing Arctic, we analyzed a large data set of particulate organic carbon (POC and nitrogen (PON measurements in first-year bottom sea ice (n = 257 from two Arctic shelves, the Canadian Arctic Archipelago and Beaufort Sea shelf, including dark winter and spring seasonal measurements. Wide ranges of sea-ice POC:PON ratios were observed during both the dark winter (12–46 mol:mol and spring (3–24 mol:mol periods. Sea-ice POC:PON ratios and chlorophyll a concentrations were significantly higher in the Archipelago versus the Beaufort Sea shelf (p < 0.01, yet there was a highly significant relationship between sea-ice POC and PON during spring for both shelves (r2 = 0.94. POC:PON ratios were not consistent over the range of measured POC and PON concentrations, justifying the use of a power function model to best describe the relationship between POC and PON. Distinct relationships between POC:PON ratios and chlorophyll-based biomass were observed for the dark winter and the spring: dark winter sea-ice POC:PON ratios decreased with increasing sea-ice biomass whereas spring POC:PON ratios increased with increasing sea-ice biomass. The transition from the dark period to the spring growth period in first-year sea ice represented a distinct stoichiometric shift in POC:PON ratios. Our results demonstrate that the Redfield ratio has limited applicability over the four-order of magnitude range of biomass concentrations observed in first-year sea ice on Arctic shelves. This study emphasizes the need for variable POC:PON stoichiometry in sea-ice biogeochemical models and budget estimates, in particular at high biomass concentrations and when considering seasonality outside of the spring period in first year ice. The use of a power function model for POC:PON relationships in sea ice is also recommended to better constrain carbon estimates in biogeochemical sea-ice models.

  7. Examples of Savannah River water dilution between the Savannah River Plant and the Beaufort-Jasper and Port Wentworth water-treatment plants

    International Nuclear Information System (INIS)

    Hayes, D.W.

    1983-01-01

    A substantial dilution of the river water occurs between the Savannah River Plant (SRP) and the two treatment plants. This dilution results from inflow of surface and groundwater and from direct rainfall. The amount of dilution was estimated to be approximately 20% and 54% down to the Port Wentworth and Beaufort-Jasper plants, respectively

  8. Hydrographic patterns in microbial communities in the density stratified Alaska Beaufort Shelf

    Science.gov (United States)

    Hamdan, L. J.; Gillevet, P. M.; Sikaroodi, M.; Greinert, J.; Treude, T.; Coffin, R. B.

    2011-12-01

    Although similar microbial communities have been observed globally in methane charged sediments, the mechanism of their dispersal is unknown. The ocean may be a physical barrier for dispersal of anaerobic microorganisms typically found in methane seeps. However, it is possible that bottom layers act as distribution conduits for dormant cells to locations where geochemical conditions would allow them to flourish. The Alaska Beaufort Shelf (ABS) was used to stage a preliminary study of dispersal patterns of microbial communities from methane influenced waters and sediments. During September 2009 three density stratified water masses were present on the ABS, including a low salinity Arctic surface layer, an intermediate Pacific layer, and a deep, cold and saline Atlantic layer. Microbial community composition was studied in each water mass and in underlying sediments to determine the influence of water mass on sediment community structure. Sediment cores were obtained using a piston corer. Water samples were retrieved using a CTD rosette, and hydrodynamic data (e.g., salinity, temperature, density, dissolved oxygen) were acquired simultaneously. Methane concentrations were measured using a GC-FID. Community composition was surveyed using Multitag Pyrosequencing (MTPS) and Length Heterogeneity-PCR (LH-PCR) by amplification of hypervariable regions of the archaeal and bacterial SSUrRNA. MTPS data were processed using the QIIME pipeline, and taxonomy was assigned using the RDP classifier. The Unifrac metric and multidimensional scaling analysis was used to determine similarity patterns. Distinct bacterial communities were evident in the three water masses. Sequences related to the SAR11 clade were highly abundant in the Arctic layer. Gammaproteobacteria related to the Thiotrichales were abundant in Pacific and Atlantic layers. Archaeal water column communities were relatively homogeneous, and unidentified Euryarchaeota dominated all three water masses. Microbial

  9. The occurrence, origin and stratigraphic significance of bone-bearing mudstone pellet conglomerates from the Beaufort group in the Jansenville district, Cape Province, South Africa

    International Nuclear Information System (INIS)

    Turner, B.R.

    1981-01-01

    The lack of useful lithostratigraphic markers in the Beaufort Group in the southern Karoo Basin has focused attention on the biostratigraphy of the sediments. As a result a more refined scheme of biostratigraphic classification is now possible which may prove useful in fixing the stratigraphic position of the uranium mineralized horizons. The most important mineralized horizon in the Beaufort West area (contains about 90 per cent of all known uranium occurrences) is associated with the Pristerognathus/Diictodon assemblage zone, but the way in which this relates to the important uranium occurrences farther east, between Graaff-Reinet and Jansenville, is uncertain because of the lack of biostratigraphic control. Vertebrate remains have recently been found in mudstone pellet conglomerates in Beaufort channel sandstones along the Bullrivier in the Jansenville District, in an area that is extensively mineralized. The sandstones were deposited as point bar sands within a meandering river system flowing towards the north-east. The rivers drained a dry, arid to semi-arid alluvial plain and were characterized by fluctuating discharge and periods of low or negligible flow. These conditions promoted flood scour and fill activity and the deposition of internal mudstone pellet conglomerates. Hydrodynamic considerations suggest that estimates of bone transport velocity from their hydrodynamically equivalent quartz sphere is of limited value and can seldom, if ever, be applied to fossil bone accumulations. Identification of the bones from the conglomerates indicates that they belong to the Dino-cephalia biozone and not the overlying Pristerognathus/Diictodon zone. This suggests that the lower part of the Beaufort succession (formerly the Tapinocephalus zone) extends farther east than previously thought, and that the main mineralized horizon in this area occurs lower down in the succession than that around Beaufort West

  10. Arctic Ocean sea ice drift origin derived from artificial radionuclides

    International Nuclear Information System (INIS)

    Camara-Mor, P.; Masque, P.; Garcia-Orellana, J.; Cochran, J.K.; Mas, J.L.; Chamizo, E.; Hanfland, C.

    2010-01-01

    Since the 1950s, nuclear weapon testing and releases from the nuclear industry have introduced anthropogenic radionuclides into the sea, and in many instances their ultimate fate are the bottom sediments. The Arctic Ocean is one of the most polluted in this respect, because, in addition to global fallout, it is impacted by regional fallout from nuclear weapon testing, and indirectly by releases from nuclear reprocessing facilities and nuclear accidents. Sea-ice formed in the shallow continental shelves incorporate sediments with variable concentrations of anthropogenic radionuclides that are transported through the Arctic Ocean and are finally released in the melting areas. In this work, we present the results of anthropogenic radionuclide analyses of sea-ice sediments (SIS) collected on five cruises from different Arctic regions and combine them with a database including prior measurements of these radionuclides in SIS. The distribution of 137 Cs and 239,240 Pu activities and the 240 Pu/ 239 Pu atom ratio in SIS showed geographical differences, in agreement with the two main sea ice drift patterns derived from the mean field of sea-ice motion, the Transpolar Drift and Beaufort Gyre, with the Fram Strait as the main ablation area. A direct comparison of data measured in SIS samples against those reported for the potential source regions permits identification of the regions from which sea ice incorporates sediments. The 240 Pu/ 239 Pu atom ratio in SIS may be used to discern the origin of sea ice from the Kara-Laptev Sea and the Alaskan shelf. However, if the 240 Pu/ 239 Pu atom ratio is similar to global fallout, it does not provide a unique diagnostic indicator of the source area, and in such cases, the source of SIS can be constrained with a combination of the 137 Cs and 239,240 Pu activities. Therefore, these anthropogenic radionuclides can be used in many instances to determine the geographical source area of sea-ice.

  11. Solar radiation interactions with seasonal sea ice

    Science.gov (United States)

    Ehn, Jens Kristian

    Presently, the Arctic Ocean is undergoing an escalating reduction in sea ice and a transition towards a seasonal sea ice environment. This warrants detailed investigations into improving our understanding of the seasonal evolution of sea ice and snow covers, and their representation in climate models. The interaction of solar radiation with sea ice is an important process influencing the energy balance and biological activity in polar seas, and consequently plays a key role in the earth's climate system. This thesis focuses on characterization of the optical properties---and the underlying physical properties that determine them---of seasonal sea ice during the fall freeze-up and the spring melt periods. Both periods display high spatial heterogeneity and rapid temporal changes in sea ice properties, and are therefore poorly understood. Field data were collected in Amundsen Gulf/Franklin Bay (FB), southern-eastern Beaufort Sea, in Oct.-Nov. 2003 and Apr. 2004 and in Button Bay (BB), western Hudson Bay, in Mar.-May 2005 to address (1) the temporal and spatial evolution of surface albedo and transmittance, (2) how radiative transfer in sea ice is controlled by its physical nature, and (3) the characteristics of the bottom ice algae community and its effect on the optical properties. The fall study showed the importance of surface features such as dry or slushy bare ice, frost flowers and snow cover in determining the surface albedo. Ice thickness was also important, however, mostly because surface features were associated with thickness. For example, nilas (brine skim layer on the surface, while surface conditions on thicker ice types were cold and dry enough to support a snow cover. In general, the surface albedo increased exponentially with an ice thickness increase, however, variability within ice thickness types were very large. It is apparent that a more complete treatment of brine movement towards the surface ice of the ice cover and the formation of surface

  12. Recent State of Arctic Sea Ice

    Science.gov (United States)

    Nghiem, S. V.; Rigor, I. G.; Clemente-Colón, P.; Perovich, D. K.; Richter-Menge, J. A.; Chao, Y.; Neumann, G.; Ortmeyer, M.

    2008-12-01

    Route, and most of two routes of the Northwest Passage, north and south of Victoria Island, which facilitated ice retreat and the opening of waterways this summer. Most importantly, the shift from a perennial to a seasonal ice covered Arctic Ocean significantly decreases the overall surface albedo resulting in enhanced solar heat absorption in spring and summer, which further decreases the Arctic ice pack through the ice albedo feedback mechanism. In early September 2008, a major melt event occurred over a large region extending from the Beaufort Sea across the Kara Sea toward the Laptev Sea, with active melt areas encroaching in the NP vicinity. This melt event was caused by an advection of warm air from the south, which melted and pushed sea ice away at the same time. At that time, the total extent of Arctic sea ice was about 0.5 million km2 (size of Spain) larger than that at the same time last year.

  13. Integrating Seismic Reflection and Ground Penetrating Radar Data at the Marine Corps Air Station, Beaufort, South Carolina

    Science.gov (United States)

    Addison, A. D.; Knapp, C. C.; Waddell, M. G.

    2006-12-01

    Extensive work has been performed at the Marine Corps Air Station (MCAS) in Beaufort South Carolina to characterize the subsurface and generate a groundwater flow model for an assessment of MCAS aquifer vulnerability and contamination potential using various hydrogeological and geophysical techniques such as slug tests, vertical seismic profiling (VSP), borehole geophysics, vertical electrical soundings, and seismic reflection surveys. The goal of the additional research is to integrate the existing seismic reflection data with newly acquired GPR data in order to: (1) demonstrate the effectiveness of the GPR as a tool for site characterization and (2) obtain hydrogeophysical parameters in a heterogeneous environment. The primary focus of the MCAS Beaufort groundwater flow model is to understand the interaction between the unconsolidated clastic Pleistocene sediments and the underlying Eocene Ocala Limestone, which is the primary aquifer. GPR data were collected along the transect of seismic reflection line MCAS-2 which is a total length of approximately 1700 m with a recording length of 500 ms. There are several wells along the profile that were utilized for hydrogeological and geophysical calibration. Preliminary GPR data were collected adjacent to ground water monitor well BFT-2368, using the 50 and 100 MHz frequency antennas, and consisted of three reflection profiles that vary in length from approximately 210 to 240 m. Comparison of the GPR and seismic data illustrate that the two applications complement one another with respect to resolution. Where GPR data contain better detail (more continuous reflectors) in the shallow subsurface, the seismic data contain less detail but deeper reflections. We are using the seismic attributes such as acoustic impedance, and the dielectric properties estimated from the GPR data in order to make assessments on hydrogeological parameters such as porosity and further, hydraulic conductivity.

  14. Crevasse splay processes and deposits in an ancient distributive fluvial system: The lower Beaufort Group, South Africa

    Science.gov (United States)

    Gulliford, Alice R.; Flint, Stephen S.; Hodgson, David M.

    2017-08-01

    Up to 12% of the mud-prone, ephemeral distributive fluvial system stratigraphy in the Permo-Triassic lower Beaufort Group, South Africa, comprises tabular fine-grained sandstone to coarse-grained siltstone bodies, which are interpreted as proximal to distal crevasse splay deposits. Crevasse splay sandstones predominantly exhibit ripple to climbing ripple cross-lamination, with some structureless and planar laminated beds. A hierarchical architectural scheme is adopted, in which 1 m thick crevasse splay elements extend for tens to several hundreds of meters laterally, and stack with other splay elements to form crevasse splay sets up to 4 m thick and several kilometers in width and length. Paleosols and nodular horizons developed during periods, or in areas, of reduced overbank flooding are used to subdivide the stratigraphy, separating crevasse splay sets. Deposits from crevasse splays differ from frontal splays as their proximal deposits are much thinner and narrower, with paleocurrents oblique to the main paleochannel. In order for crevasse splay sets to develop, the parent channel belt and the location where crevasse splays form must stay relatively fixed during a period of multiple flood events. Beaufort Group splays have similar geometries to those of contemporary perennial rivers but exhibit more lateral variability in facies, which is interpreted to be the result of more extreme fluctuations in discharge regime. Sharp-based crevasse splay packages are associated with channel avulsion, but most are characterized by a gradual coarsening upward, interpreted to represent progradation. The dominance of progradational splays beneath channel belt deposits may be more characteristic of progradational stratigraphy in a distributive fluvial system rather than dominated by avulsion processes in a trunk river system. This stratigraphic motif may therefore be an additional criterion for recognition of distributive fluvial systems in the ancient record.

  15. The Sea-Ice Floe Size Distribution

    Science.gov (United States)

    Stern, H. L., III; Schweiger, A. J. B.; Zhang, J.; Steele, M.

    2017-12-01

    The size distribution of ice floes in the polar seas affects the dynamics and thermodynamics of the ice cover and its interaction with the ocean and atmosphere. Ice-ocean models are now beginning to include the floe size distribution (FSD) in their simulations. In order to characterize seasonal changes of the FSD and provide validation data for our ice-ocean model, we calculated the FSD in the Beaufort and Chukchi seas over two spring-summer-fall seasons (2013 and 2014) using more than 250 cloud-free visible-band scenes from the MODIS sensors on NASA's Terra and Aqua satellites, identifying nearly 250,000 ice floes between 2 and 30 km in diameter. We found that the FSD follows a power-law distribution at all locations, with a seasonally varying exponent that reflects floe break-up in spring, loss of smaller floes in summer, and the return of larger floes after fall freeze-up. We extended the results to floe sizes from 10 m to 2 km at selected time/space locations using more than 50 high-resolution radar and visible-band satellite images. Our analysis used more data and applied greater statistical rigor than any previous study of the FSD. The incorporation of the FSD into our ice-ocean model resulted in reduced sea-ice thickness, mainly in the marginal ice zone, which improved the simulation of sea-ice extent and yielded an earlier ice retreat. We also examined results from 17 previous studies of the FSD, most of which report power-law FSDs but with widely varying exponents. It is difficult to reconcile the range of results due to different study areas, seasons, and methods of analysis. We review the power-law representation of the FSD in these studies and discuss some mathematical details that are important to consider in any future analysis.

  16. Canadian snow and sea ice: historical trends and projections

    Science.gov (United States)

    Mudryk, Lawrence R.; Derksen, Chris; Howell, Stephen; Laliberté, Fred; Thackeray, Chad; Sospedra-Alfonso, Reinel; Vionnet, Vincent; Kushner, Paul J.; Brown, Ross

    2018-04-01

    The Canadian Sea Ice and Snow Evolution (CanSISE) Network is a climate research network focused on developing and applying state of the art observational data to advance dynamical prediction, projections, and understanding of seasonal snow cover and sea ice in Canada and the circumpolar Arctic. Here, we present an assessment from the CanSISE Network on trends in the historical record of snow cover (fraction, water equivalent) and sea ice (area, concentration, type, and thickness) across Canada. We also assess projected changes in snow cover and sea ice likely to occur by mid-century, as simulated by the Coupled Model Intercomparison Project Phase 5 (CMIP5) suite of Earth system models. The historical datasets show that the fraction of Canadian land and marine areas covered by snow and ice is decreasing over time, with seasonal and regional variability in the trends consistent with regional differences in surface temperature trends. In particular, summer sea ice cover has decreased significantly across nearly all Canadian marine regions, and the rate of multi-year ice loss in the Beaufort Sea and Canadian Arctic Archipelago has nearly doubled over the last 8 years. The multi-model consensus over the 2020-2050 period shows reductions in fall and spring snow cover fraction and sea ice concentration of 5-10 % per decade (or 15-30 % in total), with similar reductions in winter sea ice concentration in both Hudson Bay and eastern Canadian waters. Peak pre-melt terrestrial snow water equivalent reductions of up to 10 % per decade (30 % in total) are projected across southern Canada.

  17. Seasonality of Air-sea-ice-land Variables for Arctic Tundra in Northern Eurasia and North America

    Science.gov (United States)

    Bhatt, U. S.; Walker, D. A.; Raynolds, M. K.; Steele, M.; Epstein, H.; Jia, G.; Comiso, J. C.; Pinzon, J. E.; Tucker, C. J.

    2009-12-01

    The strength of tundra productivity trends as measured by the annual maximum Normalized Difference Vegetation Index (MaxNDVI) and time integrated NDVI (TI-NDVI) vary around the Arctic over the 1982-2008 period. Our analysis suggests that the timing of terrestrial vegetation growth is connected to seasonal patterns of sea-ice concentrations, ocean temperatures and land surface temperatures. This study used SSMI estimates of sea ice concentration, based on a bootstrap algorithm and AVHRR radiometric surface temperature. Summer Warmth Index (SWI) was calculated as the sum from May to August of the degree months above freezing of surface temperature at each pixel and is an accepted measure of plant growth potential. The Normalized Difference Vegetation Index (NDVI) represents vegetation greenness and has been used extensively to monitor changes in the Arctic. The albedo of green plants varies with solar radiation wavelength, which is the basis for the NDVI index. The analysis was conducted within 50 km of the Arctic coastline to focus on the region of maximum maritime influence. Time series of regional sea-ice concentration, SWI and NDVI were constructed for the 50-km width domains for the Pan-Arctic, North America, Eurasia and Arctic subregions. Standard climate analysis techniques were applied to the regional time series to investigate the seasonality of sea ice, NDVI and SWI. MaxNDVI has increased in the 50-km land domain contiguous to the Beaufort Sea by 17% since 1982, whereas it has only increased by 3% in the coastal Kara Sea region. Analysis of semimonthly MaxNDVI indicates that the vegetation greens up more rapidly in the spring in the Beaufort than the W. Kara and the Kara has slightly higher NDVI in the fall. The climatological weekly sea ice concentrations in 50-km coastal domain displays an earlier breakup in the Beaufort and a later freeze-up in the Kara Sea area. Regional differences in the seasonal cycle can in part explain the spatially varied trends

  18. Inter-Relationship Between Subtropical Pacific Sea Surface Temperature, Arctic Sea Ice Concentration, and the North Atlantic Oscillation in Recent Summers and Winters

    Science.gov (United States)

    Lim, Young-Kwon; Cullather, Richard I.; Nowicki, Sophie M.; Kim, Kyu-Myong

    2017-01-01

    The inter-relationship between subtropical western-central Pacific sea surface temperatures (STWCPSST), sea ice concentration in the Beaufort Sea (SICBS), and the North Atlantic Oscillation (NAO) are investigated for the last 37 summers and winters (1980-2016). Lag-correlation of the STWCPSST×(-1) in spring with the NAO phase and SICBS in summer increases over the last two decades, reaching r = 0.4-0.5 with significance at 5 percent, while winter has strong correlations in approximately 1985-2005. Observational analysis and the atmospheric general circulation model experiments both suggest that STWCPSST warming acts to increase the Arctic geopotential height and temperature in the following season. This atmospheric response extends to Greenland, providing favorable conditions for developing the negative phase of the NAO. SIC and surface albedo tend to decrease over the Beaufort Sea in summer, linked to the positive surface net shortwave flux. Energy balance considering radiative and turbulent fluxes reveal that available energy that can heat surface is larger over the Arctic and Greenland and smaller over the south of Greenland, in response to the STWCPSST warming in spring. XXXX Arctic & Atlantic: Positive upper-level height/T anomaly over the Arctic and Greenland, and a negative anomaly over the central-eastern Atlantic, resembling the (-) phase of the NAO. Pacific: The negative height/T anomaly over the mid-latitudes, along with the positive anomaly over the STWCP, where 1degC warming above climatology is prescribed. Discussion: It is likely that the Arctic gets warm and the NAO is in the negative phase in response to the STWCP warming. But, there are other factors (e.g., internal variability) that contribute to determination of the NAO phase: not always the negative phase of the NAO in the event of STWCP warming (e.g.: recent winters and near neutral NAO in 2017 summer).

  19. Geology and mineral resources of the Florence, Beaufort, Rocky Mount, and Norfolk 10 x 20 NTMS quadrangles. National Uranium Resource Evaluation program

    International Nuclear Information System (INIS)

    Harris, W.B.

    1982-08-01

    This document provides geologic and mineral resources data for previously-issued Savannah River Laboratory hydrogeochemical and stream sediment reports of the Beaufort, Florence, Norfolk, and Rocky Mount 1 0 x 2 0 National Topographic Map Series quadrangles in the southeastern United States. This report is issued in draft form, without detailed technical and copy editing. This was done to make the report available to the public before the end of the National Uranium Resource Evaluation program

  20. Geology and mineral resources of the Florence, Beaufort, Rocky Mount, and Norfolk 1/sup 0/ x 2/sup 0/ NTMS quadrangles. National Uranium Resource Evaluation program

    Energy Technology Data Exchange (ETDEWEB)

    Harris, W.B.

    1982-08-01

    This document provides geologic and mineral resources data for previously-issued Savannah River Laboratory hydrogeochemical and stream sediment reports of the Beaufort, Florence, Norfolk, and Rocky Mount 1/sup 0/ x 2/sup 0/ National Topographic Map Series quadrangles in the southeastern United States. This report is issued in draft form, without detailed technical and copy editing. This was done to make the report available to the public before the end of the National Uranium Resource Evaluation program.

  1. Physical control of the distributions of a key Arctic copepod in the Northeast Chukchi Sea

    Science.gov (United States)

    Elliott, Stephen M.; Ashjian, Carin J.; Feng, Zhixuan; Jones, Benjamin; Chen, Changsheng; Zhang, Yu

    2017-10-01

    The Chukchi Sea is a highly advective regime dominated by a barotropically driven northward flow modulated by wind driven currents that reach the bottom boundary layer of this shallow environment. A general northward gradient of decreasing temperature and food concentration leads to geographically divergent copepod growth and development rates between north and south. The physics of this system establish the biological connection potential between specific regions. The copepod Calanus glacialis is a key grazer, predator, and food source in Arctic shelf seas. Its summer distribution and abundance have direct effects on much of the food web, from phytoplankton to migrating bowhead whales. In August 2012 and 2013, C. glacialis distributions were quantified over Hanna Shoal in the northeast Chukchi Sea. Here an individual-based model with Lagrangian tracking and copepod life stage development capabilities is used to advect and develop these distributions forward and backward in time to determine the source (production locations) and sink (potential overwintering locations) regions of the transient Hanna Shoal C. glacialis population. Hanna Shoal supplies diapause competent C. glacialis to both the Beaufort Slope and the Chukchi Cap, mainly receives juveniles from the broad slope between Hanna Shoal and Herald Valley and receives second year adults from as far south as the Anadyr Gulf and as near as the broad slope between Hanna Shoal and Herald Valley. The 2013 sink region was shifted west relative to the 2012 region and the 2013 adult source region was shifted north relative to the 2012 adult source region. These connection potentials were not sensitive to precise times and locations of release, but were quite sensitive to depth of release. These patterns demonstrate how interannual differences in the physical conditions well south of Hanna Shoal play a critical role in determining the abundance and distribution of a key food source over Hanna Shoal and in the

  2. The delivery of organic contaminants to the Arctic food web: why sea ice matters.

    Science.gov (United States)

    Pućko, Monika; Stern, Gary A; Macdonald, Robie W; Jantunen, Liisa M; Bidleman, Terry F; Wong, Fiona; Barber, David G; Rysgaard, Søren

    2015-02-15

    For decades sea ice has been perceived as a physical barrier for the loading of contaminants to the Arctic Ocean. We show that sea ice, in fact, facilitates the delivery of organic contaminants to the Arctic marine food web through processes that: 1) are independent of contaminant physical-chemical properties (e.g. 2-3-fold increase in exposure to brine-associated biota), and 2) depend on physical-chemical properties and, therefore, differentiate between contaminants (e.g. atmospheric loading of contaminants to melt ponds over the summer, and their subsequent leakage to the ocean). We estimate the concentrations of legacy organochlorine pesticides (OCPs) and current-use pesticides (CUPs) in melt pond water in the Beaufort Sea, Canadian High Arctic, in 2008, at near-gas exchange equilibrium based on Henry's law constants (HLCs), air concentrations and exchange dynamics. CUPs currently present the highest risk of increased exposures through melt pond loading and drainage due to the high ratio of melt pond water to seawater concentration (Melt pond Enrichment Factor, MEF), which ranges from 2 for dacthal to 10 for endosulfan I. Melt pond contaminant enrichment can be perceived as a hypothetical 'pump' delivering contaminants from the atmosphere to the ocean under ice-covered conditions, with 2-10% of CUPs annually entering the Beaufort Sea via this input route compared to the standing stock in the Polar Mixed Layer of the ocean. The abovementioned processes are strongly favored in first-year ice compared to multi-year ice and, therefore, the dynamic balance between contaminant inventories and contaminant deposition to the surface ocean is being widely affected by the large-scale icescape transition taking place in the Arctic. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Arctic sea ice in the global eddy-permitting ocean reanalysis ORAP5

    Science.gov (United States)

    Tietsche, Steffen; Balmaseda, Magdalena A.; Zuo, Hao; Mogensen, Kristian

    2017-08-01

    We discuss the state of Arctic sea ice in the global eddy-permitting ocean reanalysis Ocean ReAnalysis Pilot 5 (ORAP5). Among other innovations, ORAP5 now assimilates observations of sea ice concentration using a univariate 3DVar-FGAT scheme. We focus on the period 1993-2012 and emphasize the evaluation of model performance with respect to recent observations of sea ice thickness. We find that sea ice concentration in ORAP5 is close to assimilated observations, with root mean square analysis residuals of less than 5 % in most regions. However, larger discrepancies exist for the Labrador Sea and east of Greenland during winter owing to biases in the free-running model. Sea ice thickness is evaluated against three different observational data sets that have sufficient spatial and temporal coverage: ICESat, IceBridge and SMOSIce. Large-scale features like the gradient between the thickest ice in the Canadian Arctic and thinner ice in the Siberian Arctic are simulated well by ORAP5. However, some biases remain. Of special note is the model's tendency to accumulate too thick ice in the Beaufort Gyre. The root mean square error of ORAP5 sea ice thickness with respect to ICESat observations is 1.0 m, which is on par with the well-established PIOMAS model sea ice reconstruction. Interannual variability and trend of sea ice volume in ORAP5 also compare well with PIOMAS and ICESat estimates. We conclude that, notwithstanding a relatively simple sea ice data assimilation scheme, the overall state of Arctic sea ice in ORAP5 is in good agreement with observations and will provide useful initial conditions for predictions.

  4. Regional Forecast of the Minimum Sea Ice Extent: a Lagrangian Approach

    Science.gov (United States)

    Tremblay, B.; Brunette, C.

    2016-02-01

    In this contribution we extend the pan-Arctic analysis presented in Williams et al. (2015) to produce a regional forecast of sea-ice conditions for each of the Arctic peripheral seas including the Beaufort, Chukchi, East Siberian, Laptev and Kara seas. The model builds on the finding that the mean large scale sea ice circulation the previous winter determines where the following summer minimum sea ice extent. We show that, in particular, the mid to late winter coastal sea-ice divergence plays a major role. When ice divergence occurs late in the winter, new ice forms but it does not have the time to grow to sufficient thickness to survive the following summer melt. To produce a regional forecast, we use a Lagrangian sea-ice model to backtrack an imaginary line defining the boundary of a given sea, starting from the beginning of the melt season in June and ending in November of the previous year. Results show that the position of the ice edge in each of the peripheral seas of the Arctic is well correlated with the previous winter's divergence. The maximum correlation is obtained when the synthetic ice edge is backtracked from May to February. Note that, unlike the previous pan-Arctic study of Williams and colleagues in which the net ice divergence could be correlated with the winter mean Arctic Oscillation index, this regional analysis requires sea ice drifts in order to calculate the winter mean ice divergence along the coast. This finding supports the need for continuous production of real-time satellite-derived sea-ice velocity vectors, which can now be used for observation-based regional forecasting.

  5. Prevalence and Antibiogram Profiling of Escherichia coli Pathotypes Isolated from the Kat River and the Fort Beaufort Abstraction Water

    Directory of Open Access Journals (Sweden)

    Nolonwabo Nontongana

    2014-08-01

    Full Text Available Escherichia coli is a widespread bacterium encompassing a variety of strains, ranging from highly pathogenic strains, causing worldwide outbreaks of severe diseases to avirulent, well characterized safe laboratory strains. This study evaluated the prevalence and antibiogram profiles of E. coli pathotypes isolated from the Kat River and Fort Beaufort abstraction water. A total of 171 out of 278 confirmed E. coli isolates were positive for at least one pathogenic determinant and these included enteropathogenic E. coli (6%, enterotoxigenic E. coli (47%, uropathogenic E. coli (2%, neonatal meningitis E. coli (5%, diffusely adherent E. coli (1% and enterohaemorrhagic E. coli (1%. Interestingly, enteroinvasive and enteroaggregative E. coli were not detected. The phenotypic antibiogram profiles of the isolates revealed that all were resistant to penicillin G, while 98% and 38% of the pathotypes were resistant to ampicillin and trimethoprim-sulphamethoxazole, respectively. About 8% of the isolates were resistant to streptomycin. More than half of the isolates exhibited multiple antibiotic resistance with 44% being resistant to three antibiotics and 8% resistant to four antibiotics. We conclude that the Kat River is a reservoir of potentially virulent antibiotic resistant E. coli strains that can cause serious health risks to humans who drink raw water from this river, or in the case that consumption of treated drinking water coincides with failed drinking water processes.

  6. Evaluation of Structural Best Management Practices for Highway Runoff in Beaufort and Colleton Counties, South Carolina, 2005-2006

    Science.gov (United States)

    Conlon, Kevin; Journey, Celeste

    2009-01-01

    As part of the National Pollutant Discharge Elimination System (NPDES) permit program mandated in the Clean Water Act, the South Carolina Department of Transportation (SCDOT) is required to address the quality of stormwater runoff from state-maintained roadways. From 2005 to 2006, the SCDOT and the U.S. Geological Survey (USGS) worked cooperatively in Beaufort and Colleton Counties, South Carolina (SC), to evaluate the performance of four different structural devices that served as best management practices (BMPs). These structural devices were installed to lessen the potential effects of stormwater runoff on water quality in waterways near state roads. The purpose of this Fact Sheet is to summarize results published in the USGS Scientific Investigations Report 2008-5150. The report documents the ability of these four BMP devices to remove suspended sediment, metals, nutrients, and organics compounds in stormwater runoff. The quantity of rainfall and stormflow and quality of stormwater entering and leaving the BMPs were monitored during 12-13 storms over a 21-month period. The results provide the SCDOT with quantitative information to evaluate whether or not the BMPs effectively enhanced stormwater quality. This information can be used by the SCDOT and other State, local, and Federal agencies in the selection of appropriate BMPs for future installation.

  7. Estimation of Melt Ponds over Arctic Sea Ice using MODIS Surface Reflectance Data

    Science.gov (United States)

    Ding, Y.; Cheng, X.; Liu, J.

    2017-12-01

    Melt ponds over Arctic sea ice is one of the main factors affecting variability of surface albedo, increasing absorption of solar radiation and further melting of snow and ice. In recent years, a large number of melt ponds have been observed during the melt season in Arctic. Moreover, some studies have suggested that late spring to mid summer melt ponds information promises to improve the prediction skill of seasonal Arctic sea ice minimum. In the study, we extract the melt pond fraction over Arctic sea ice since 2000 using three bands MODIS weekly surface reflectance data by considering the difference of spectral reflectance in ponds, ice and open water. The preliminary comparison shows our derived Arctic-wide melt ponds are in good agreement with that derived by the University of Hamburg, especially at the pond distribution. We analyze seasonal evolution, interannual variability and trend of the melt ponds, as well as the changes of onset and re-freezing. The melt pond fraction shows an asymmetrical growth and decay pattern. The observed melt ponds fraction is almost within 25% in early May and increases rapidly in June and July with a high fraction of more than 40% in the east of Greenland and Beaufort Sea. A significant increasing trend in the melt pond fraction is observed for the period of 2000-2017. The relationship between melt pond fraction and sea ice extent will be also discussed. Key Words: melt ponds, sea ice, Arctic

  8. Transport of contaminants by Arctic sea ice and surface ocean currents

    International Nuclear Information System (INIS)

    Pfirman, S.

    1995-01-01

    Sea ice and ocean currents transport contaminants in the Arctic from source areas on the shelves, to biologically active regions often more than a thousand kilometers away. Coastal regions along the Siberian margin are polluted by discharges of agricultural, industrial and military wastes in river runoff, from atmospheric deposition and ocean dumping. The Kara Sea is of particular concern because of deliberate dumping of radioactive waste, as well as the large input of polluted river water. Contaminants are incorporated in ice during suspension freezing on the shelves, and by atmospheric deposition during drift. Ice releases its contaminant load through brine drainage, surface runoff of snow and meltwater, and when the floe disintegrates. The marginal ice zone, a region of intense biological activity, may also be the site of major contaminant release. Potentially contaminated ice from the Kara Sea is likely to influence the marginal ice zones of the Barents and Greenland seas. From studies conducted to date it appears that sea ice from the Kara Sea does not typically enter the Beaufort Gyre, and thus is unlikely to affect the northern Canadian and Alaskan margins

  9. Reduced body size and cub recruitment in polar bears associated with sea ice decline

    Science.gov (United States)

    Rode, K.D.; Amstrup, Steven C.; Regehr, E.V.

    2010-01-01

    Rates of reproduction and survival are dependent upon adequate body size and condition of individuals. Declines in size and condition have provided early indicators of population decline in polar bears (Ursus maritimus) near the southern extreme of their range. We tested whether patterns in body size, condition, and cub recruitment of polar bears in the southern Beaufort Sea of Alaska were related to the availability of preferred sea ice habitats and whether these measures and habitat availability exhibited trends over time, between 1982 and 2006. The mean skull size and body length of all polar bears over three years of age declined over time, corresponding with long-term declines in the spatial and temporal availability of sea ice habitat. Body size of young, growing bears declined over time and was smaller after years when sea ice availability was reduced. Reduced litter mass and numbers of yearlings per female following years with lower availability of optimal sea ice habitat, suggest reduced reproductive output and juvenile survival. These results, based on analysis of a longterm data set, suggest that declining sea ice is associated with nutritional limitations that reduced body size and reproduction in this population. ?? 2010 by the Ecological Society of America.

  10. Seasonal sea ice predictions for the Arctic based on assimilation of remotely sensed observations

    Science.gov (United States)

    Kauker, F.; Kaminski, T.; Ricker, R.; Toudal-Pedersen, L.; Dybkjaer, G.; Melsheimer, C.; Eastwood, S.; Sumata, H.; Karcher, M.; Gerdes, R.

    2015-10-01

    The recent thinning and shrinking of the Arctic sea ice cover has increased the interest in seasonal sea ice forecasts. Typical tools for such forecasts are numerical models of the coupled ocean sea ice system such as the North Atlantic/Arctic Ocean Sea Ice Model (NAOSIM). The model uses as input the initial state of the system and the atmospheric boundary condition over the forecasting period. This study investigates the potential of remotely sensed ice thickness observations in constraining the initial model state. For this purpose it employs a variational assimilation system around NAOSIM and the Alfred Wegener Institute's CryoSat-2 ice thickness product in conjunction with the University of Bremen's snow depth product and the OSI SAF ice concentration and sea surface temperature products. We investigate the skill of predictions of the summer ice conditions starting in March for three different years. Straightforward assimilation of the above combination of data streams results in slight improvements over some regions (especially in the Beaufort Sea) but degrades the over-all fit to independent observations. A considerable enhancement of forecast skill is demonstrated for a bias correction scheme for the CryoSat-2 ice thickness product that uses a spatially varying scaling factor.

  11. Arctic sea ice a major determinant in Mandt's black guillemot movement and distribution during non-breeding season

    Science.gov (United States)

    Divoky, G.J.; Douglas, David C.; Stenhouse, I. J.

    2016-01-01

    Mandt's black guillemot (Cepphus grylle mandtii) is one of the few seabirds associated in all seasons with Arctic sea ice, a habitat that is changing rapidly. Recent decreases in summer ice have reduced breeding success and colony size of this species in Arctic Alaska. Little is known about the species' movements and distribution during the nine month non-breeding period (September–May), when changes in sea ice extent and composition are also occurring and predicted to continue. To examine bird movements and the seasonal role of sea ice to non-breeding Mandt's black guillemots, we deployed and recovered (n = 45) geolocators on individuals at a breeding colony in Arctic Alaska during 2011–2015. Black guillemots moved north to the marginal ice zone (MIZ) in the Beaufort and Chukchi seas immediately after breeding, moved south to the Bering Sea during freeze-up in December, and wintered in the Bering Sea January–April. Most birds occupied the MIZ in regions averaging 30–60% sea ice concentration, with little seasonal variation. Birds regularly roosted on ice in all seasons averaging 5 h d−1, primarily at night. By using the MIZ, with its roosting opportunities and associated prey, black guillemots can remain in the Arctic during winter when littoral waters are completely covered by ice.

  12. Report of the workshop on age estimation in beluga: Beaufort, North Carolina, US 5-9 December 2011

    Directory of Open Access Journals (Sweden)

    Christina Lockyer

    2016-02-01

    Full Text Available A workshop convened by C. Lockyer and A. A. Hohn to examine variation among readers in estimating beluga ages was held in Beaufort, North Carolina, US. Terms of Reference for the workshop included the following: 1.  Provide a guide as to acceptable levels of accuracy and precision for age reading that will enable ages to be used in population models. 2.  Conduct an inter-reader/laboratory comparison for calibration and standardization of age readings from GLG counts among all readers/laboratories. 3.  Provide information on validation that will enable GLG counts to be translated to real age. 4.  Produce a manual of guidelines for the preparation and reading of GLGs in beluga teeth. Presentations by participants are abstracted here. Then we report on the processes used to compare sections, images, and interpretation, and generate guidelines for best practices in beluga age estimation. A comparative study quantified differences among readers and found that precision of experienced readers was good, higher than reported for other odontocetes. Participants agreed that counting GLGs using well prepared thin sections was preferred because they are simpler to prepare than stained sections and there was more agreement among readers compared to using half sections. Examination of teeth from captive beluga as both untreated sections and stained sections and did not clarify the reading of wild beluga teeth. This Workshop concurred with Workshop 1 (Tampa 26-27 November 2011 that interpreting one GLG as an annual record is irrefutable. Guidelines for best practices were developed.

  13. Arctic Ocean outflow and glacier-ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland)

    DEFF Research Database (Denmark)

    Dmitrenko, Igor A.; Kirillov, Sergey A.; Rudels, Bert

    2017-01-01

    the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has...... glacier outlet, colder and turbid water intrusions were observed at the base of the halocline. On the temperature-salinity plots these stations indicate a mixing line that is different from the ambient water and seems to be conditioned by the ocean-glacier interaction. Our observations of Pacific water...... are set within the context of upstream observations in the Beaufort Sea and downstream observations from the Northeast Water Polynya, and clearly show the modification of Pacific water during its advection across the Arctic Ocean. Moreover, ambient water over the Wandel Sea slope shows different...

  14. Arctic Ocean outflow and glacier-ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland)

    DEFF Research Database (Denmark)

    Dmitrenko, Igor A.; Kirillov, Sergey A.; Rudels, Bert

    2017-01-01

    glacier outlet, colder and turbid water intrusions were observed at the base of the halocline. On the temperature-salinity plots these stations indicate a mixing line that is different from the ambient water and seems to be conditioned by the ocean-glacier interaction. Our observations of Pacific water...... the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has...... are set within the context of upstream observations in the Beaufort Sea and downstream observations from the Northeast Water Polynya, and clearly show the modification of Pacific water during its advection across the Arctic Ocean. Moreover, ambient water over the Wandel Sea slope shows different...

  15. Potential Arctic sea ice refuge for sustaining a remnant polar bear population (Invited)

    Science.gov (United States)

    Durner, G. M.; Amstrup, S. C.; Douglas, D. C.; Gautier, D. L.

    2010-12-01

    Polar bears depend on sea ice as a platform from which they capture seals. Sea ice availability must be spatially and temporally adequate for birth and weaning of seal pups, and to maximize seal hunting opportunities for polar bears. Projected declines in the spatial and temporal extent of summer and autumn sea ice could potentially limit the ability of polar bears to build up body stores sufficient to maintain reproductive fitness. General circulation models, however, suggest that summer and autumn sea ice may persist in the shelf waters of the Canadian Archipelago and northern Greenland adjacent to the Arctic basin. While winter-formed ice is important, a primary mechanism for sea ice accumulation in this region is by mechanical thickening of the sea ice facilitated by convergent forces from the Beaufort Gyre and the Transpolar Drift Stream. Collectively these areas could provide a polar bear refugium when other regions have lost the sea ice necessary to support viable populations. The potential for a polar bear refugium, however, must include other resource considerations. Projected declines of sea ice in the Northwest Passage may expose polar bears to hazards related to increase shipping and other commerce. Increasing global demands and limited opportunities elsewhere make the Arctic an increasingly attractive area for petroleum exploration. The Canadian Archipelago coincides with the Sverdrup basin, where petroleum accumulations have already been discovered but as yet are undeveloped. The Lincoln Sea Basin offshore of northern Greenland has the geological possibility of significant petroleum accumulations, and northeastern Greenland is one of the most prospective areas in the Arctic for undiscovered oil. Activities associated with commerce and petroleum development could reduce the potential viability of the region as a polar bear refugium. Hence, if the goal is a sustainable (albeit reduced) polar bear population, important considerations include commerce

  16. Sea Ice

    Science.gov (United States)

    Perovich, D.; Gerland, S.; Hendricks, S.; Meier, Walter N.; Nicolaus, M.; Richter-Menge, J.; Tschudi, M.

    2013-01-01

    During 2013, Arctic sea ice extent remained well below normal, but the September 2013 minimum extent was substantially higher than the record-breaking minimum in 2012. Nonetheless, the minimum was still much lower than normal and the long-term trend Arctic September extent is -13.7 per decade relative to the 1981-2010 average. The less extreme conditions this year compared to 2012 were due to cooler temperatures and wind patterns that favored retention of ice through the summer. Sea ice thickness and volume remained near record-low levels, though indications are of slightly thicker ice compared to the record low of 2012.

  17. Arctic Ocean sea ice drift origin derived from artificial radionuclides.

    Science.gov (United States)

    Cámara-Mor, P; Masqué, P; Garcia-Orellana, J; Cochran, J K; Mas, J L; Chamizo, E; Hanfland, C

    2010-07-15

    Since the 1950s, nuclear weapon testing and releases from the nuclear industry have introduced anthropogenic radionuclides into the sea, and in many instances their ultimate fate are the bottom sediments. The Arctic Ocean is one of the most polluted in this respect, because, in addition to global fallout, it is impacted by regional fallout from nuclear weapon testing, and indirectly by releases from nuclear reprocessing facilities and nuclear accidents. Sea-ice formed in the shallow continental shelves incorporate sediments with variable concentrations of anthropogenic radionuclides that are transported through the Arctic Ocean and are finally released in the melting areas. In this work, we present the results of anthropogenic radionuclide analyses of sea-ice sediments (SIS) collected on five cruises from different Arctic regions and combine them with a database including prior measurements of these radionuclides in SIS. The distribution of (137)Cs and (239,240)Pu activities and the (240)Pu/(239)Pu atom ratio in SIS showed geographical differences, in agreement with the two main sea ice drift patterns derived from the mean field of sea-ice motion, the Transpolar Drift and Beaufort Gyre, with the Fram Strait as the main ablation area. A direct comparison of data measured in SIS samples against those reported for the potential source regions permits identification of the regions from which sea ice incorporates sediments. The (240)Pu/(239)Pu atom ratio in SIS may be used to discern the origin of sea ice from the Kara-Laptev Sea and the Alaskan shelf. However, if the (240)Pu/(239)Pu atom ratio is similar to global fallout, it does not provide a unique diagnostic indicator of the source area, and in such cases, the source of SIS can be constrained with a combination of the (137)Cs and (239,240)Pu activities. Therefore, these anthropogenic radionuclides can be used in many instances to determine the geographical source area of sea-ice. Copyright 2010 Elsevier B.V. All

  18. Analysis of Sea Ice Cover Sensitivity in Global Climate Model

    Directory of Open Access Journals (Sweden)

    V. P. Parhomenko

    2014-01-01

    Full Text Available The paper presents joint calculations using a 3D atmospheric general circulation model, an ocean model, and a sea ice evolution model. The purpose of the work is to analyze a seasonal and annual evolution of sea ice, long-term variability of a model ice cover, and its sensitivity to some parameters of model as well to define atmosphere-ice-ocean interaction.Results of 100 years simulations of Arctic basin sea ice evolution are analyzed. There are significant (about 0.5 m inter-annual fluctuations of an ice cover.The ice - atmosphere sensible heat flux reduced by 10% leads to the growth of average sea ice thickness within the limits of 0.05 m – 0.1 m. However in separate spatial points the thickness decreases up to 0.5 m. An analysis of the seasonably changing average ice thickness with decreasing, as compared to the basic variant by 0.05 of clear sea ice albedo and that of snow shows the ice thickness reduction in a range from 0.2 m up to 0.6 m, and the change maximum falls for the summer season of intensive melting. The spatial distribution of ice thickness changes shows, that on the large part of the Arctic Ocean there was a reduction of ice thickness down to 1 m. However, there is also an area of some increase of the ice layer basically in a range up to 0.2 m (Beaufort Sea. The 0.05 decrease of sea ice snow albedo leads to reduction of average ice thickness approximately by 0.2 m, and this value slightly depends on a season. In the following experiment the ocean – ice thermal interaction influence on the ice cover is estimated. It is carried out by increase of a heat flux from ocean to the bottom surface of sea ice by 2 W/sq. m in comparison with base variant. The analysis demonstrates, that the average ice thickness reduces in a range from 0.2 m to 0.35 m. There are small seasonal changes of this value.The numerical experiments results have shown, that an ice cover and its seasonal evolution rather strongly depend on varied parameters

  19. Mechanisms influencing seasonal to inter-annual prediction skill of sea ice extent in the Arctic Ocean in MIROC

    Science.gov (United States)

    Ono, Jun; Tatebe, Hiroaki; Komuro, Yoshiki; Nodzu, Masato I.; Ishii, Masayoshi

    2018-02-01

    To assess the skill of seasonal to inter-annual predictions of the detrended sea ice extent in the Arctic Ocean (SIEAO) and to clarify the underlying physical processes, we conducted ensemble hindcasts, started on 1 January, 1 April, 1 July and 1 October for each year from 1980 to 2011, for lead times up to three years, using the Model for Interdisciplinary Research on Climate (MIROC) version 5 initialised with the observed atmosphere and ocean anomalies and sea ice concentration. Significant skill is found for the winter months: the December SIEAO can be predicted up to 11 months ahead (anomaly correlation coefficient is 0.42). This skill might be attributed to the subsurface ocean heat content originating in the North Atlantic. A plausible mechanism is as follows: the subsurface water flows into the Barents Sea from spring to fall and emerges at the surface in winter by vertical mixing, and eventually affects the sea ice variability there. Meanwhile, the September SIEAO predictions are skillful for lead times of up to two months, due to the persistence of sea ice in the Beaufort, Chukchi, and East Siberian seas initialised in July, as suggested by previous studies.

  20. Cross-stratified Wood: Enigmatic Woody Debris Deposits in Warm-Polar Fluvial Sediments (Pliocene Beaufort Formation, Nunavut)

    Science.gov (United States)

    Davies, N. S.; Gosse, J. C.; Rybczynski, N.

    2012-04-01

    Woody debris has been an important sediment component and a significant geomorphic agent in pristine fluvial systems since the Devonian. In recent years a large volume of research has focussed on various aspects of the importance of woody debris within the fluvial realm; from the evolutionary significance of fossil wood accumulations in the rock record to studies of the biogeomorphological and ecological importance of woody debris in modern rivers. In this presentation we describe cross-stratified woody debris deposits comprising organic detritus from a boreal-type treeline forest that included species of pine, birch, poplar, alder, spruce, eastern cedar, and larch, in both shrub and tree form. The cross-stratified wood is an enigmatic subset of fine woody debris which, to our knowledge, has never before been described from either the global stratigraphic record or modern fluvial environments. The deposits we describe are located within the Pliocene Beaufort Formation on Meighen Island, Nunavut, Canada, at a latitude of 80°N, and are compared with other cross-stratified woody debris deposits that have been noted elsewhere in the Pliocene of the Canadian Arctic. We make the robust observation that these deposits appear to be geographically and stratigraphically restricted to polar latitudes from a period of warm climatic conditions during the Pliocene (15-20 °C warmer mean annual temperature than the present day). In this regard it is possible to speculate that the transport of large amounts of woody debris as bedload is potentially a unique feature of forested high latitude rivers. Such bedload deposition requires a large amount of woody debris with a greater density than the fluid transporting it. The softwood composition of the debris suggests that this was most likely attained by saturation and subsequent entrainment of extensive accumulations of deadwood, promoted by unusually high rates of tree mortality and low rates of bacterial decomposition arising from

  1. Do common eiders nest in kin groups? Microgeographic genetic structure in a philopatric sea duck

    Science.gov (United States)

    Sonsthagen, S.A.; Talbot, S.L.; Lanctot, Richard B.; McCracken, K.G.

    2010-01-01

    We investigated local genetic associations among female Pacific common eiders (Somateria mollissima v-nigrum) nesting in a stochastic Arctic environment within two groups of barrier islands (Simpson Lagoon and Mikkelsen Bay) in the Beaufort Sea, Alaska. Nonrandom genetic associations were observed among nesting females using regional spatial autocorrelation analyses for distance classes up to 1000 m in Simpson Lagoon. Nearest-neighbour analyses identified clusters of genetically related females with positive lr values observed for 0-13% and 0-7% of the comparisons in Simpson Lagoon and Mikkelsen Bay, respectively, across years. These results indicate that a proportion of females are nesting in close proximity to more genetically related individuals, albeit at low frequency. Such kin groupings may form through active association between relatives or through natal philopatry and breeding site fidelity. Eiders nest in close association with driftwood, which is redistributed annually by seasonal storms. Yet, genetic associations were still observed. Microgeographic structure may thus be more attributable to kin association than natal philopatry and site fidelity. However, habitat availability may also influence the level of structure observed. Regional structure was present only within Simpson Lagoon and this island group includes at least three islands with sufficient driftwood for colonies, whereas only one island at Mikkelsen Bay has these features. A long-term demographic study is needed to understand more fully the mechanisms that lead to fine-scale genetic structure observed in common eiders breeding in the Beaufort Sea. ?? Published 2010. This article is a US Government work and is in the public domain in the USA.

  2. Shallow methylmercury production in the marginal sea ice zone of the central Arctic Ocean.

    Science.gov (United States)

    Heimbürger, Lars-Eric; Sonke, Jeroen E; Cossa, Daniel; Point, David; Lagane, Christelle; Laffont, Laure; Galfond, Benjamin T; Nicolaus, Marcel; Rabe, Benjamin; van der Loeff, Michiel Rutgers

    2015-05-20

    Methylmercury (MeHg) is a neurotoxic compound that threatens wildlife and human health across the Arctic region. Though much is known about the source and dynamics of its inorganic mercury (Hg) precursor, the exact origin of the high MeHg concentrations in Arctic biota remains uncertain. Arctic coastal sediments, coastal marine waters and surface snow are known sites for MeHg production. Observations on marine Hg dynamics, however, have been restricted to the Canadian Archipelago and the Beaufort Sea (Ocean (79-90 °N) profiles for total mercury (tHg) and MeHg. We find elevated tHg and MeHg concentrations in the marginal sea ice zone (81-85 °N). Similar to other open ocean basins, Arctic MeHg concentration maxima also occur in the pycnocline waters, but at much shallower depths (150-200 m). The shallow MeHg maxima just below the productive surface layer possibly result in enhanced biological uptake at the base of the Arctic marine food web and may explain the elevated MeHg concentrations in Arctic biota. We suggest that Arctic warming, through thinning sea ice, extension of the seasonal sea ice zone, intensified surface ocean stratification and shifts in plankton ecodynamics, will likely lead to higher marine MeHg production.

  3. Ecosystem function and particle flux dynamics across the Mackenzie Shelf (Beaufort Sea, Arctic Ocean: an integrative analysis of spatial variability and biophysical forcings

    Directory of Open Access Journals (Sweden)

    A. Forest

    2013-05-01

    Full Text Available A better understanding of how environmental changes affect organic matter fluxes in Arctic marine ecosystems is sorely needed. Here we combine mooring times series, ship-based measurements and remote sensing to assess the variability and forcing factors of vertical fluxes of particulate organic carbon (POC across the Mackenzie Shelf in 2009. We developed a geospatial model of these fluxes to proceed to an integrative analysis of their determinants in summer. Flux data were obtained with sediment traps moored around 125 m and via a regional empirical algorithm applied to particle size distributions (17 classes from 0.08–4.2 mm measured by an Underwater Vision Profiler 5. The low fractal dimension (i.e., porous, fluffy particles derived from the algorithm (1.26 ± 0.34 and the dominance (~ 77% of rapidly sinking small aggregates (p r2 cum. = 0.37. Bacteria were correlated with small aggregates, while northeasterly wind was associated with large size classes (> 1 mm ESD, but these two factors were weakly related with each other. Copepod biomass was overall negatively correlated (p < 0.05 with vertical POC fluxes, implying that metazoans acted as regulators of export fluxes, even if their role was minor given that our study spanned the onset of diapause. Our results demonstrate that on interior Arctic shelves where productivity is low in mid-summer, localized upwelling zones (nutrient enrichment may result in the formation of large filamentous phytoaggregates that are not substantially retained by copepod and bacterial communities.

  4. BIOGEOGRAPHIC DISTRIBUTIONS, ABUNDANCES, AND VULNERABILITIES TO CLIMATE CHANGE OF BRACHYURAN AND LITHODID CRABS FROM THE GULF OF CALIFORNIA TO THE BEAUFORT SEA - 9-19-2014

    Science.gov (United States)

    As part of an EPA/USGS project to predict the relative vulnerability of near-coastal species to climate change we analyzed the biogeographic and abundance patterns of the brachyuran or ‘True’ crabs (n=368) and lithodid or ‘King’ crabs (n=20) that are found...

  5. BIOGEOGRAPHIC DISTRIBUTIONS, ABUNDANCES, AND VULNERABILITIES TO CLIMATE CHANGE OF BRACHYURAN AND LITHODID CRABS FROM THE GULF OF CALIFORNIA TO THE BEAUFORT SEA

    Science.gov (United States)

    As part of an EPA/USGS project to predict the relative vulnerability of near-coastal species to climate change we analyzed the biogeographic and abundance patterns of the brachyuran or ‘True’ crabs (n=368) and lithodid or ‘King’ crabs (n=20) that are found...

  6. CRABS IN CRISIS:BIOGEOGRAPHIC DISTRIBUTIONS, ABUNDANCES, AND VULNERABILITIES TO CLIMATE CHANGE OF BRACHYURAN AND LITHODID CRABS FROM THE GULF OF CALIFORNIA TO THE BEAUFORT SEA

    Science.gov (United States)

    To predict the relative vulnerability of near-coastal species to climate change we analyzed the biogeographic and abundance patterns of the brachyuran or ‘True’ crabs (n=368) and lithodid or ‘King’ crabs (n=20) that are found in the twelve MEOW (“Mar...

  7. Shore Ice Ride-Up and Pile-Up Features. Part 2. Alaska’s Beaufort Sea Coast--1983 and 1984,

    Science.gov (United States)

    1984-09-01

    Operations. Corps. He also appreciates the technical review of the manuscript provided by Dr. 4 Gordon F.N. Cox and Dr. Devinder S. Sodhi of CRREL. RE.. p...i,atd. hp 111c: Ii, i !J2 ’ ’AC! t~ a,, seeu frollt tile top ot tile cast end oit thle diore 1Cc tI 11 I d’ k0 c r :-. I: ice pile-uip lookingi 1,~t...8217 Conference. Commission on phe. The Arctic Policy Review , November. History and Culture, North Slope Borough, Bar- " Anonymom (1983a) From Ketchikan to

  8. Ecosystem monitoring information collected from Norseman II in Beaufort Sea for the ANIMIDA III project from 2014-07-31 to 2015-08-12 (NCEI Accession 0162530)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains physical, chemical, and biological data collected during research cruises for the Arctic Nearshore Impact Monitoring in Development Area...

  9. Blood-based biomarkers of selenium and thyroid status indicate possible adverse biological effects of mercury and polychlorinated biphenyls in Southern Beaufort Sea polar bears.

    Science.gov (United States)

    Knott, Katrina K; Schenk, Patricia; Beyerlein, Susan; Boyd, Daryle; Ylitalo, Gina M; O'Hara, Todd M

    2011-11-01

    We examined biomarkers of selenium status (whole blood Se; serum Se; glutathione peroxidase activity) and thyroid status (concentrations and ratios of thyroxine, T4; tri-iodothyronine, T3; albumin) in polar bears to assess variations among cohorts, and relationships to circulating concentrations of contaminants. Concentrations of total mercury (Hg) in whole blood were similar among cohorts (prime aged males and females, older animals, ages≥16 years, and young animals, ages 1-5 years; 48.44±35. 81; p=0.253). Concentrations of sum of seven polychlorinated biphenyls (∑PCB7) in whole blood were greater in females (with and without cubs, 26.44±25.82 ng/g ww) and young (26.81±10.67 ng/g ww) compared to males (8.88±5.76 ng/g ww, p0.08). Thyroid hormones were greater in females (solitary females and females with cubs) compared to males (ppolar bears (ppolar bears were more susceptible to changes in blood-based biomarkers of selenium and thyroid status than males. Further classifications of the physiologic states of polar bears and repeated measures of individuals over time are needed to accurately assess the biological impact of combined toxicant exposures. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Final environmental impact statement, Beaufort Sea oil and gas development/Northstar Project. Appendix A: BP Exploration (Alaska) Inc. Final project description - Revision 1, March 27, 1997

    International Nuclear Information System (INIS)

    1999-02-01

    BP Exploration (Alaska) Inc. (BPXA) submitted a permit application to the US Army Engineer District, Alaska to initiate the review process for BPXA's plans to develop and produce oil and gas from the Northstar Unit. This report contains Appendix A of an Environmental Impact Statement which was undertaken to identify and evaluate the potential effects the proposed project may have on the environment. This document is the Northstar Development Project, Final Project Description, Revision 1 for BPXA Northstar Project

  11. Bowhead Whale Feeding Ecology Study (BOWFEST): Aerial Survey in Chukchi and Beaufort Seas conducted from 2007-08-23 to 2011-09-16 (NCEI Accession 0131425)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Bowhead Whale Feeding Ecology Study (BOWFEST) was initiated in May 2007 through an Interagency Agreement between the Bureau of Ocean Energy Management (BOEM)...

  12. A weekly Arctic sea-ice thickness data record from merged CryoSat-2 and SMOS satellite data

    Science.gov (United States)

    Ricker, Robert; Hendricks, Stefan; Kaleschke, Lars; Tian-Kunze, Xiangshan; King, Jennifer; Haas, Christian

    2017-07-01

    Sea-ice thickness on a global scale is derived from different satellite sensors using independent retrieval methods. Due to the sensor and orbit characteristics, such satellite retrievals differ in spatial and temporal resolution as well as in the sensitivity to certain sea-ice types and thickness ranges. Satellite altimeters, such as CryoSat-2 (CS2), sense the height of the ice surface above the sea level, which can be converted into sea-ice thickness. Relative uncertainties associated with this method are large over thin ice regimes. Another retrieval method is based on the evaluation of surface brightness temperature (TB) in L-band microwave frequencies (1.4 GHz) with a thickness-dependent emission model, as measured by the Soil Moisture and Ocean Salinity (SMOS) satellite. While the radiometer-based method looses sensitivity for thick sea ice (> 1 m), relative uncertainties over thin ice are significantly smaller than for the altimetry-based retrievals. In addition, the SMOS product provides global sea-ice coverage on a daily basis unlike the altimeter data. This study presents the first merged product of complementary weekly Arctic sea-ice thickness data records from the CS2 altimeter and SMOS radiometer. We use two merging approaches: a weighted mean (WM) and an optimal interpolation (OI) scheme. While the weighted mean leaves gaps between CS2 orbits, OI is used to produce weekly Arctic-wide sea-ice thickness fields. The benefit of the data merging is shown by a comparison with airborne electromagnetic (AEM) induction sounding measurements. When compared to airborne thickness data in the Barents Sea, the merged product has a root mean square deviation (RMSD) of about 0.7 m less than the CS2 product and therefore demonstrates the capability to enhance the CS2 product in thin ice regimes. However, in mixed first-year (FYI) and multiyear (MYI) ice regimes as in the Beaufort Sea, the CS2 retrieval shows the lowest bias.

  13. Sea salt

    OpenAIRE

    Galvis-Sánchez, Andrea C.; Lopes, João Almeida; Delgadillo, Ivone; Rangel, António O. S. S.

    2013-01-01

    The geographical indication (GI) status links a product with the territory and with the biodiversity involved. Besides, the specific knowledge and cultural practices of a human group that permit transforming a resource into a useful good is protected under a GI designation. Traditional sea salt is a hand-harvested product originating exclusively from salt marshes from specific geographical regions. Once salt is harvested, no washing, artificial drying or addition of anti-caking agents are all...

  14. Simulating Arctic clouds during Arctic Radiation- IceBridge Sea and Ice Experiment (ARISE)

    Science.gov (United States)

    Bromwich, D. H.; Hines, K. M.; Wang, S. H.

    2015-12-01

    The representation within global and regional models of the extensive low-level cloud cover over polar oceans remains a critical challenge for quantitative studies and forecasts of polar climate. In response, the polar-optimized version of the Weather Research and Forecasting model (Polar WRF) is used to simulate the meteorology, boundary layer, and Arctic clouds during the September-October 2014 Arctic Radiation- IceBridge Sea and Ice Experiment (ARISE) project. Polar WRF was developed with several adjustments to the sea ice thermodynamics in WRF. ARISE was based out of Eielson Air Force Base near Fairbanks, Alaska and included multiple instrumented C-130 aircraft flights over open water and sea ice of the Beaufort Sea. Arctic boundary layer clouds were frequently observed within cold northeasterly flow over the open ocean and ice. Preliminary results indicate these clouds were primarily liquid water, with characteristics differing between open water and sea ice surfaces. Simulated clouds are compared to ARISE observations. Furthermore, Polar WRF simulations are run for the August-September 2008 Arctic Summer Cloud Ocean Study (ASCOS) for comparison to the ARISE. Preliminary analysis shows that simulated low-level water clouds over the sea ice are too extensive during the the second half of the ASCOS field program. Alternatives and improvements to the Polar WRF cloud schemes are considered. The goal is to use the ARISE and ASCOS observations to achieve an improved polar supplement to the WRF code for open water and sea ice that can be provided to the Polar WRF community.

  15. Arctic sea-ice ridges—Safe heavens for sea-ice fauna during periods of extreme ice melt?

    Science.gov (United States)

    Gradinger, Rolf; Bluhm, Bodil; Iken, Katrin

    2010-01-01

    The abundances and distribution of metazoan within-ice meiofauna (13 stations) and under-ice fauna (12 stations) were investigated in level sea ice and sea-ice ridges in the Chukchi/Beaufort Seas and Canada Basin in June/July 2005 using a combination of ice coring and SCUBA diving. Ice meiofauna abundance was estimated based on live counts in the bottom 30 cm of level sea ice based on triplicate ice core sampling at each location, and in individual ice chunks from ridges at four locations. Under-ice amphipods were counted in situ in replicate ( N=24-65 per station) 0.25 m 2 quadrats using SCUBA to a maximum water depth of 12 m. In level sea ice, the most abundant ice meiofauna groups were Turbellaria (46%), Nematoda (35%), and Harpacticoida (19%), with overall low abundances per station that ranged from 0.0 to 10.9 ind l -1 (median 0.8 ind l -1). In level ice, low ice algal pigment concentrations (Turbellaria, Nematoda and Harpacticoida also were observed in pressure ridges (0-200 ind l -1, median 40 ind l -1), although values were highly variable and only medians of Turbellaria were significantly higher in ridge ice than in level ice. Median abundances of under-ice amphipods at all ice types (level ice, various ice ridge structures) ranged from 8 to 114 ind m -2 per station and mainly consisted of Apherusa glacialis (87%), Onisimus spp. (7%) and Gammarus wilkitzkii (6%). Highest amphipod abundances were observed in pressure ridges at depths >3 m where abundances were up to 42-fold higher compared with level ice. We propose that the summer ice melt impacted meiofauna and under-ice amphipod abundance and distribution through (a) flushing, and (b) enhanced salinity stress at thinner level sea ice (less than 3 m thickness). We further suggest that pressure ridges, which extend into deeper, high-salinity water, become accumulation regions for ice meiofauna and under-ice amphipods in summer. Pressure ridges thus might be crucial for faunal survival during periods of

  16. A brief lithostratigraphic review of the Abrahamskraal and Koonap formations of the Beaufort Group, South Africa: Towards a basin-wide stratigraphic scheme for the Middle Permian Karoo

    Science.gov (United States)

    Day, Michael Oliver; Rubidge, Bruce Sidney

    2014-12-01

    The basal strata of the Beaufort Group of the South African Karoo Basin, comprising the western Abrahamskraal and eastern Koonap formations, contain the most time extensive record of Middle Permian fossil tetrapods and hold the key to understanding Middle Permian biodiversity change in the continental realm. To determine faunal stratigraphic ranges a reliable lithostratigraphic framework for Middle Permian Beaufort deposits is essential. Until now this has proved difficult to achieve, largely due to the homogeneity of the fluvial succession coupled with structural complexity as a result of Cape Fold Belt orogenesis. Accordingly, the Abrahamskraal Formation has been only locally subdivided on the basis of sandstone packages but regional stratigraphic subdivision has not yet achieved satisfactorily. Collation of stratigraphic sections from around the Karoo Basin for this study demonstrates the presence of four sandstone packages are present within the Abrahamskraal Formation in the south-western corner of the basin. These sandstone packages are given member status, based upon the nomenclature of Le Roux (1985) with the addition of the newly recognised Grootfontein Member. The Combrinkskraal and Grootfontein Members occur in the lower half of the Abrahamskraal Formation and are laterally persistent along the southern margin of the basin. The Koornplaats Member is more restricted to the south west corner of the basin, where it quite thick, suggesting the narrowing of the highly channelized area. The overlying Moordenaars Member, more extensive towards the north than underlying packages, indicates subsequent northwesterly expansion of the locus of active channelization with time. Although thin sandstone packages in the more easterly positioned and stratigraphically equivalent Koonap Formation, this does not facilitate lithostratigraphic subdivision of this part of the stratigraphic succession and may indicate a different form of fluvial architecture. Our study provides

  17. Airborne Surveys of Snow Depth over Arctic Sea Ice

    Science.gov (United States)

    Kwok, R.; Panzer, B.; Leuschen, C.; Pang, S.; Markus, T.; Holt, B.; Gogineni, S.

    2011-01-01

    During the spring of 2009, an ultrawideband microwave radar was deployed as part of Operation IceBridge to provide the first cross-basin surveys of snow thickness over Arctic sea ice. In this paper, we analyze data from three approx 2000 km transects to examine detection issues, the limitations of the current instrument, and the regional variability of the retrieved snow depth. Snow depth is the vertical distance between the air \\snow and snow-ice interfaces detected in the radar echograms. Under ideal conditions, the per echogram uncertainty in snow depth retrieval is approx 4 - 5 cm. The finite range resolution of the radar (approx 5 cm) and the relative amplitude of backscatter from the two interfaces limit the direct retrieval of snow depths much below approx 8 cm. Well-defined interfaces are observed over only relatively smooth surfaces within the radar footprint of approx 6.5 m. Sampling is thus restricted to undeformed, level ice. In early April, mean snow depths are 28.5 +/- 16.6 cm and 41.0 +/- 22.2 cm over first-year and multiyear sea ice (MYI), respectively. Regionally, snow thickness is thinner and quite uniform over the large expanse of seasonal ice in the Beaufort Sea, and gets progressively thicker toward the MYI cover north of Ellesmere Island, Greenland, and the Fram Strait. Snow depth over MYI is comparable to that reported in the climatology by Warren et al. Ongoing improvements to the radar system and the utility of these snow depth measurements are discussed.

  18. Trends in the breeding population of Adelie penguins in the Ross Sea, 1981-2012: a coincidence of climate and resource extraction effects.

    Directory of Open Access Journals (Sweden)

    Phil O'B Lyver

    Full Text Available Measurements of the size of Adélie penguin (Pygoscelis adeliae colonies of the southern Ross Sea are among the longest biologic time series in the Antarctic. We present an assessment of recent annual variation and trends in abundance and growth rates of these colonies, adding to the published record not updated for more than two decades. High angle oblique aerial photographic surveys of colonies were acquired and penguins counted for the breeding seasons 1981-2012. In the last four years the numbers of Adélie penguins in the Ross and Beaufort Island colonies (southern Ross Sea metapopulation reached their highest levels since aerial counts began in 1981. Results indicated that 855,625 pairs of Adélie penguins established breeding territories in the western Ross Sea, with just over a quarter (28% of those in the southern portion, constituting a semi-isolated metapopulation (three colonies on Ross Island, one on nearby Beaufort Island. The southern population had a negative per capita growth rate of -0.019 during 1981-2000, followed by a positive per capita growth rate of 0.067 for 2001-2012. Colony growth rates for this metapopulation showed striking synchrony through time, indicating that large-scale factors influenced their annual growth. In contrast to the increased colony sizes in the southern population, the patterns of change among colonies of the northern Ross Sea were difficult to characterize. Trends were similar to southern colonies until the mid-1990s, after which the signal was lost owing to significantly reduced frequency of surveys. Both climate factors and recovery of whale populations likely played roles in the trends among southern colonies until 2000, after which depletion of another trophic competitor, the Antarctic toothfish (Dissostichus mawsoni, may explain the sharp increasing trend evident since then.

  19. Gene flow on ice: the role of sea ice and whaling in shaping Holarctic genetic diversity and population differentiation in bowhead whales (Balaena mysticetus).

    Science.gov (United States)

    Elizabeth Alter, S; Rosenbaum, Howard C; Postma, Lianne D; Whitridge, Peter; Gaines, Cork; Weber, Diana; Egan, Mary G; Lindsay, Melissa; Amato, George; Dueck, Larry; Brownell, Robert L; Heide-Jørgensen, Mads-Peter; Laidre, Kristin L; Caccone, Gisella; Hancock, Brittany L

    2012-11-01

    Sea ice is believed to be a major factor shaping gene flow for polar marine organisms, but it remains unclear to what extent it represents a true barrier to dispersal for arctic cetaceans. Bowhead whales are highly adapted to polar sea ice and were targeted by commercial whalers throughout Arctic and subarctic seas for at least four centuries, resulting in severe reductions in most areas. Both changing ice conditions and reductions due to whaling may have affected geographic distribution and genetic diversity throughout their range, but little is known about range-wide genetic structure or whether it differed in the past. This study represents the first examination of genetic diversity and differentiation across all five putative stocks, including Baffin Bay-Davis Strait, Hudson Bay-Foxe Basin, Bering-Beaufort-Chukchi, Okhotsk, and Spitsbergen. We also utilized ancient specimens from Prince Regent Inlet (PRI) in the Canadian Arctic and compared them with modern stocks. Results from analysis of molecular variance and demographic simulations are consistent with recent and high gene flow between Atlantic and Pacific stocks in the recent past. Significant genetic differences between ancient and modern populations suggest PRI harbored unique maternal lineages in the past that have been recently lost, possibly due to loss of habitat during the Little Ice Age and/or whaling. Unexpectedly, samples from this location show a closer genetic relationship with modern Pacific stocks than Atlantic, supporting high gene flow between the central Canadian Arctic and Beaufort Sea over the past millennium despite extremely heavy ice cover over much of this period.

  20. The thermodynamic state of the Arctic atmosphere observed by AIRS: comparisons during the record minimum sea ice extents of 2007 and 2012

    Directory of Open Access Journals (Sweden)

    A. Devasthale

    2013-08-01

    Full Text Available The record sea ice minimum (SIM extents observed during the summers of 2007 and 2012 in the Arctic are stark evidence of accelerated sea ice loss during the last decade. Improving our understanding of the Arctic atmosphere and accurate quantification of its characteristics becomes ever more crucial, not least to improve predictions of such extreme events in the future. In this context, the Atmospheric Infrared Sounder (AIRS instrument onboard NASA's Aqua satellite provides crucial insights due to its ability to provide 3-D information on atmospheric thermodynamics. Here, we facilitate comparisons in the evolution of the thermodynamic state of the Arctic atmosphere during these two SIM events using a decade-long AIRS observational record (2003–2012. It is shown that the meteorological conditions during 2012 were not extreme, but three factors of preconditioning from winter through early summer played an important role in accelerating sea ice melt. First, the marginal sea ice zones along the central Eurasian and North Atlantic sectors remained warm throughout winter and early spring in 2012 preventing thicker ice build-up. Second, the circulation pattern favoured efficient sea ice transport out of the Arctic in the Atlantic sector during late spring and early summer in 2012 compared to 2007. Third, additional warming over the Canadian archipelago and southeast Beaufort Sea from May onward further contributed to accelerated sea ice melt. All these factors may have lead the already thin and declining sea ice cover to pass below the previous sea ice extent minimum of 2007. In sharp contrast to 2007, negative surface temperature anomalies and increased cloudiness were observed over the East Siberian and Chukchi seas in the summer of 2012. The results suggest that satellite-based monitoring of atmospheric preconditioning could be a critical source of information in predicting extreme sea ice melting events in the Arctic.

  1. Method to characterize directional changes in Arctic sea ice drift and associated deformation due to synoptic atmospheric variations using Lagrangian dispersion statistics

    Directory of Open Access Journals (Sweden)

    J. V. Lukovich

    2017-07-01

    Full Text Available A framework is developed to assess the directional changes in sea ice drift paths and associated deformation processes in response to atmospheric forcing. The framework is based on Lagrangian statistical analyses leveraging particle dispersion theory which tells us whether ice drift is in a subdiffusive, diffusive, ballistic, or superdiffusive dynamical regime using single-particle (absolute dispersion statistics. In terms of sea ice deformation, the framework uses two- and three-particle dispersion to characterize along- and across-shear transport as well as differential kinematic parameters. The approach is tested with GPS beacons deployed in triplets on sea ice in the southern Beaufort Sea at varying distances from the coastline in fall of 2009 with eight individual events characterized. One transition in particular follows the sea level pressure (SLP high on 8 October in 2009 while the sea ice drift was in a superdiffusive dynamic regime. In this case, the dispersion scaling exponent (which is a slope between single-particle absolute dispersion of sea ice drift and elapsed time changed from superdiffusive (α ∼ 3 to ballistic (α ∼ 2 as the SLP was rounding its maximum pressure value. Following this shift between regimes, there was a loss in synchronicity between sea ice drift and atmospheric motion patterns. While this is only one case study, the outcomes suggest similar studies be conducted on more buoy arrays to test momentum transfer linkages between storms and sea ice responses as a function of dispersion regime states using scaling exponents. The tools and framework developed in this study provide a unique characterization technique to evaluate these states with respect to sea ice processes in general. Application of these techniques can aid ice hazard assessments and weather forecasting in support of marine transportation and indigenous use of near-shore Arctic areas.

  2. Serum antibody levels against select bacterial pathogens in Atlantic bottlenose dolphins, Tursiops truncatus, from Beaufort NC USA and Charleston Harbor, Charleston, SC, USA.

    Science.gov (United States)

    Beck, B M; Rice, C D

    2003-03-01

    Concern over the emergence of zoonotic diseases in marine organisms is growing. In response to this concern, this study set out to measure antibody activities against bacterial pathogens in Atlantic bottlenose dolphins, Tursiops truncatus, from the coastal estuaries of NC and SC, USA. Individuals from Charleston SC harbor, a heavily industrialized shipping harbor estuary, and from Beaufort NC, a non-shipping estuary, were examined. Purified IgG was obtained from pooled sera using ammonium sulfate precipitation steps and protein-G procedures, which was then used to generate a panel of IgG-specific monoclonal antibodies. Two of these antibodies, mAbs BB-10-2 (IgG1) and BB-32-2 (IgG2b), were then used to determine total serum IgG concentrations using a sandwich capture ELISA. Circulating IgG levels were variable between individuals and between the two pods. MAb BB-10-2 was then used in an indirect ELISA to determine serum antibody activities against several common marine bacteria as well as the human pathogens E. coli and E. coli strain 0157:H7, Vibrio parahemolyticus, V. vulnificus, V. cholerae, Mycobacteria marinum, M. fortuitum, and M. chelonae. The highest antibody activities were against mycobacteria, two of which are zoonotic pathogens. Males had the highest antibody activities, thus suggesting low cell-mediated immunity against intracellular pathogens in these individuals. T-cell proliferation in response to Con-A, an indicator of cell-mediated immune function, was then measured in the Beaufort population. Males had the lowest proliferation responses, however a negative correlation between antibody activities and T-cell proliferation in individuals could not be established for either of the Mycobacteria species. Overall, antibody activities against all bacteria, including innocuous species such as V. anguillarum, V. natrigens, and M. xenopi were highly variable between individual dolphins and the two pods, with some animals exhibiting very high activities

  3. Dramatic variability of the carbonate system at a temperate coastal ocean site (Beaufort, North Carolina, USA is regulated by physical and biogeochemical processes on multiple timescales.

    Directory of Open Access Journals (Sweden)

    Zackary I Johnson

    Full Text Available Increasing atmospheric carbon dioxide (CO2 from anthropogenic sources is acidifying marine environments resulting in potentially dramatic consequences for the physical, chemical and biological functioning of these ecosystems. If current trends continue, mean ocean pH is expected to decrease by ~0.2 units over the next ~50 years. Yet, there is also substantial temporal variability in pH and other carbon system parameters in the ocean resulting in regions that already experience change that exceeds long-term projected trends in pH. This points to short-term dynamics as an important layer of complexity on top of long-term trends. Thus, in order to predict future climate change impacts, there is a critical need to characterize the natural range and dynamics of the marine carbonate system and the mechanisms responsible for observed variability. Here, we present pH and dissolved inorganic carbon (DIC at time intervals spanning 1 hour to >1 year from a dynamic, coastal, temperate marine system (Beaufort Inlet, Beaufort NC USA to characterize the carbonate system at multiple time scales. Daily and seasonal variation of the carbonate system is largely driven by temperature, alkalinity and the balance between primary production and respiration, but high frequency change (hours to days is further influenced by water mass movement (e.g. tides and stochastic events (e.g. storms. Both annual (~0.3 units and diurnal (~0.1 units variability in coastal ocean acidity are similar in magnitude to 50 year projections of ocean acidity associated with increasing atmospheric CO2. The environmental variables driving these changes highlight the importance of characterizing the complete carbonate system rather than just pH. Short-term dynamics of ocean carbon parameters may already exert significant pressure on some coastal marine ecosystems with implications for ecology, biogeochemistry and evolution and this shorter term variability layers additive effects and

  4. Holocene Paleoceanography of the Chukchi Sea / Alaskan Margin, Western Arctic Ocean

    Science.gov (United States)

    McKay, J. L.; Hillaire-Marcel, C.; de Vernal, A.; Polyak, L.; Darby, D.

    2006-12-01

    A multi-proxy approach to the analysis of deep-sea sediment cores has been used to investigate paleoceanographical changes in the western Arctic. This approach includes stable isotopic analysis of{ \\it Neogloboquadrina pachyderma} (Np), the dominant planktonic foraminifera in the Arctic, which lives along the pycnocline that separates the cold, low salinity surface water from the underlying warmer water mass of North Atlantic origin. Palynological analyses focus on dinocyst assemblages that are usually well preserved in Arctic seas and include several species, thus allowing treatment of data (modern analogue technique) for quantitative reconstruction of sea-surface parameters, including maximum summer temperature and seasonal extent of sea-ice cover (cf. de Vernal et al., Paleoceanography, 2005). Work in the Chukchi Sea has shown that larger (i.e., heavier, possibly mature) specimens of Np are characterized by a lower oxygen isotopic composition relative to smaller (i.e., possibly juvenile) specimens that live at shallower depths, reflecting calcification of larger Np shells on top of the warmer North Atlantic Water mass (cf. Hillaire-Marcel et al., Quat. Sci. Rev., 2004). These results suggest that a reverse thermocline (warmer water underlying colder water) persisted throughout the Holocene, and that the gradients between surface and subsurface waters were stronger during the early Holocene, which may indicate greater influx of North Atlantic Water at this time. It is also possible that the isotopic composition of the planktonic foraminifera was influenced by enhanced sea-ice formation and sinking of isotopically-light brines during the early Holocene. This second hypothesis is compatible with reconstructions from dinocysts that suggest maximum sea-ice extent during the early Holocene. Preliminary results from core HLY0501-05 collected in the Beaufort Sea off the Alaskan Margin during Leg 1 of the HOTRAX 2005 Expedition show results consistent with those of the

  5. Quantifying Sea-Ice Loss as a Driver of Arctic Coastal Erosion

    Science.gov (United States)

    Overeem, I.; Wobus, C. W.; Anderson, R. S.; Clow, G. D.; Urban, F. E.; Stanton, T. P.

    2009-12-01

    Rapid erosion along the Arctic coast has highlighted the susceptibility of northern shorelines to changes in climate. Recent studies suggest a correlation between rapid coastline retreat and warming temperatures. Rapid coastal change coincides with declines in sea ice extent, which allows increase of sea surface temperature (SST), and inevitably exposes Arctic coastlines to increasing wave attack. Observations over a ~3 km transect of frozen, silty bluffs along the Beaufort Sea Coast at Drew Point, Alaska show an average annual loss of 12-15 m of coastline over 2007-2009. Locally, rates are as high as 25 m/yr. The lack of significant inflections across transitions to more sandy stretches of coastline suggests that sandy spits regress landward at similar rates during storm events. We quantify the impact of sea ice loss on the Arctic coast by using ‘open water season duration’ and ‘open water distance’ normal to the coast as first order proxies for erosion potential. Sea ice concentrations have been analyzed using Nimbus 7-SMMR /SSM/I and DMSP SSMI Passive Microwave data, which runs from 1978 to the present at daily or two-daily time resolution. The data cover the entire Arctic region at 25 by 25 km. Locally at Drew Point, the open water time window increases progressively over time and the high erosion years of 2004 and 2007 stand out as having large open water distances. Observed local temperature, solar radiation and wind records drive approximations of SST warming and wave energy. Our hypothesis is that areas of the coastal zone that experience significant changes in open water season and open water distance will be more vulnerable to changes due to ocean storm erosion and thermal notching by waves. Actual erosion is also importantly influenced by dominant wind directions, local bathymetry and specific time series of storm tracks.

  6. The Effects of Changing Sea Ice on Marine Mammals and Their Hunters in Northern Alaska

    Science.gov (United States)

    Huntington, H.; Quakenbush, L.; Nelson, M.

    2015-12-01

    Marine mammals are important sources of food for indigenous residents of northern Alaska. Changing sea ice patterns affect the animals themselves as well as access by hunters. Documenting the traditional knowledge of Iñupiaq and Yupik hunters concerning marine mammals and sea ice makes accessible a wide range of information and insight relevant to ecological understanding, conservation action, and the regulation of human activity. We interviewed hunters in villages from northern Bering Sea to the Beaufort Sea, focusing on bowhead whales, walrus, and ice seals. Hunters reported extensive changes in sea ice, with resulting effects on the timing of marine mammal migrations, the distribution and behavior of the animals, and the efficacy of certain hunting methods, for example the difficulty of finding ice thick enough to support a bowhead whale for butchering. At the same time, hunters acknowledged impacts and potential impacts from changing technology such as more powerful outboard engines and from industrial activity such as shipping and oil and gas development. Hunters have been able to adapt to some changes, for example by hunting bowhead whales in fall as well as spring on St. Lawrence Island, or by focusing their hunt in a shorter period in Nuiqsut to accommodate work schedules and worse weather. Other changes, such as reduced availability of ice seals due to rapid retreat of pack ice after spring break-up, continue to defy easy responses. Continued environmental changes, increased disturbance from human activity, and the introduction of new regulations for hunting may further challenge the ability of hunters to provide food as they have done to date, though innovation and flexibility may also provide new sources of adaptation.

  7. Increased Arctic Sea Ice Drift Alters Polar Bear Movements and Energetics

    Science.gov (United States)

    Douglas, D. C.; Durner, G. M.; Albeke, S. E.; Whiteman, J. P.; Amstrup, S. C.; Richardson, E.; Wilson, R. R.; Ben-David, M.

    2015-12-01

    Recent thinning of Arctic sea ice has increased its drift from currents and winds. Increased ice drift could affect movements and energy balance of polar bears (Ursus maritimus) which rely, almost exclusively, on this substrate for hunting seals. Foraging by polar bears is a relatively sedentary behavior, as they typically capture their main prey by waiting at breathing holes, where seals haul-out along leads, or by short-distance stalking. We examined the response of polar bears to ice drift in the Beaufort (BS) and Chukchi (CS) seas, and between two periods with different sea ice characteristics: 1987-1998 and 1999-2013. We used satellite-tracked adult female polar bear locations, standardized by a continuous-time correlated random walk, coupled with modeled ice drift, to estimate displacement and drift-corrected bear movements along east-west and north-south axes. Sea ice drift in both regions increased with greater westward and more extreme northward and southward rates from 1987-1998 to 1999-2013. Polar bears responded with greater eastward movements and, in the CS greater movements north and south. We show that efforts by polar bears to compensate for greater westward ice drift in recent years translated into a model-derived estimate of 5.7-7.2% increase in energy expenditure. We also estimated that polar bears increased their travel time 18-20% between the two time periods, suggesting time allocated to foraging was reduced. Increased energetic costs and travel time resulting from greater ice drift, in conjunction with ongoing habitat loss, suggest that recent changes to Arctic sea ice may affect movements and energy balance of polar bears.

  8. Impacts of early autumn Arctic sea ice concentration on subsequent spring Eurasian surface air temperature variations

    Science.gov (United States)

    Chen, Shangfeng; Wu, Renguang

    2017-11-01

    This study reveals a close relation between autumn Arctic sea ice change (SIC) in the Laptev Sea-eastern Siberian Sea-Beaufort Sea and subsequent spring Eurasian surface air temperature (SAT) variation. Specifically, more (less) SIC over the above regions in early autumn generally correspond to SAT warming (cooling) over the mid-high latitudes of Eurasia during subsequent spring. Early autumn Arctic SIC affects spring Eurasian SAT via modulating spring Arctic Oscillation (AO) associated atmospheric changes. The meridional temperature gradient over the mid-high latitudes decreases following the Arctic sea ice loss. This results in deceleration of prevailing westerly winds over the mid-latitudes of the troposphere, which leads to increase in the upward propagation of planetary waves and associated Eliassen-Palm flux convergence in the stratosphere over the mid-high latitudes. Thereby, westerly winds in the stratosphere are reduced and the polar vortex is weakened. Through the wave-mean flow interaction and downward propagation of zonal wind anomalies, a negative spring AO pattern is formed in the troposphere, which favors SAT cooling over Eurasia. The observed autumn Arctic SIC-spring Eurasian SAT connection is reproduced in the historical simulation (1850-2005) of the flexible global ocean-atmosphere-land system model, spectral version 2 (FGOALS-s2). The FGOALS-s2 also simulates the close connection between autumn SIC and subsequent spring AO. Further analysis suggests that the prediction skill of the spring Eurasian SAT was enhanced when taking the autumn Arctic SIC signal into account.

  9. Consequences of long-distance swimming and travel over deep-water pack ice for a female polar bear during a year of extreme sea ice retreat

    Science.gov (United States)

    Durner, G.M.; Whiteman, J.P.; Harlow, H.J.; Amstrup, Steven C.; Regehr, E.V.; Ben-David, M.

    2011-01-01

    Polar bears (Ursus maritimus) prefer to live on Arctic sea ice but may swim between ice floes or between sea ice and land. Although anecdotal observations suggest that polar bears are capable of swimming long distances, no data have been available to describe in detail long distance swimming events or the physiological and reproductive consequences of such behavior. Between an initial capture in late August and a recapture in late October 2008, a radio-collared adult female polar bear in the Beaufort Sea made a continuous swim of 687 km over 9 days and then intermittently swam and walked on the sea ice surface an additional 1,800 km. Measures of movement rate, hourly activity, and subcutaneous and external temperature revealed distinct profiles of swimming and walking. Between captures, this polar bear lost 22% of her body mass and her yearling cub. The extraordinary long distance swimming ability of polar bears, which we confirm here, may help them cope with reduced Arctic sea ice. Our observation, however, indicates that long distance swimming in Arctic waters, and travel over deep water pack ice, may result in high energetic costs and compromise reproductive fitness. ?? 2011 US Government.

  10. Paleomagnetism and Magnetostratigraphy of Upper Permian to Lower Triassic (?) Beaufort Group Strata at Bethulie, Karoo Basin, Free State Province, South Africa

    Science.gov (United States)

    Geissman, J. W.; Gastaldo, R. A.; Neveling, J.; Makubalo, S.

    2017-12-01

    A multifaceted approach to understand the timing of interpreted environmental changes during the Late Permian to possibly Early Triassic (?) time in the Beaufort Group strata of the Karoo Basin includes work to establish robust magnetic polarity records for sections previously interpreted to encompass end-Permian extinction events. Demonstrating the preservation of an early-acquired remanence (RM) in Karoo strata is required for a robust magnetostratigraphy. Yet, this is challenging due to thermochemical effects related to the Early Jurassic (ca. 183 Ma) Karoo Large Igneous Province (LIP), and the NE to SW increase in burial diagenesis attending Cape Fold Belt tectonism. Documentation of a primary RM in these strata, which appears to be preserved in some areas, requires careful laboratory- and field-based assessment. We report data from 53 sites collected at the well-studied Bethulie section, Free State Province, in which several 50 mA/m). Collectively, we interpret these data to indicate that any ChRM, with the exception of those from host strata in baked contacts, that persists above Tlub of 425oC is pre-Karoo LIP in origin, and likely primary at the Bethulie locality.

  11. Aral Sea basin: a sea dies, a sea also rises.

    Science.gov (United States)

    Glantz, Michael H

    2007-06-01

    The thesis of this article is quite different from many other theses of papers, books, and articles on the Aral Sea. It is meant to purposely highlight the reality of the situation in Central Asia: the Aral Sea that was once a thriving body of water is no more. That sea is dead. What does exist in its place are the Aral seas: there are in essence three bodies of water, one of which is being purposefully restored and its level is rising (the Little Aral), and two others which are still marginally connected, although they continue to decline in level (the Big Aral West and the Big Aral East). In 1960 the level of the sea was about 53 m above sea level. By 2006 the level had dropped by 23 m to 30 m above sea level. This was not a scenario generated by a computer model. It was a process of environmental degradation played out in real life in a matter of a few decades, primarily as a result of human activities. Despite wishes and words to the contrary, it will take a heroic global effort to save what remains of the Big Aral. It would also take a significant degree of sacrifice by people and governments in the region to restore the Big Aral to an acceptable level, given that the annual rate of flow reaching the Amudarya River delta is less than a 10th of what it was several decades ago. Conferring World Heritage status to the Aral Sea(s) could spark restoration efforts for the Big Aral.

  12. Melt ponds on Arctic sea ice determined from MODIS satellite data using an artificial neural network

    Directory of Open Access Journals (Sweden)

    A. Rösel

    2012-04-01

    Full Text Available Melt ponds on sea ice strongly reduce the surface albedo and accelerate the decay of Arctic sea ice. Due to different spectral properties of snow, ice, and water, the fractional coverage of these distinct surface types can be derived from multispectral sensors like the Moderate Resolution Image Spectroradiometer (MODIS using a spectral unmixing algorithm. The unmixing was implemented using a multilayer perceptron to reduce computational costs.

    Arctic-wide melt pond fractions and sea ice concentrations are derived from the level 3 MODIS surface reflectance product. The validation of the MODIS melt pond data set was conducted with aerial photos from the MELTEX campaign 2008 in the Beaufort Sea, data sets from the National Snow and Ice Data Center (NSIDC for 2000 and 2001 from four sites spread over the entire Arctic, and with ship observations from the trans-Arctic HOTRAX cruise in 2005. The root-mean-square errors range from 3.8 % for the comparison with HOTRAX data, over 10.7 % for the comparison with NSIDC data, to 10.3 % and 11.4 % for the comparison with MELTEX data, with coefficient of determination ranging from R2=0.28 to R2=0.45. The mean annual cycle of the melt pond fraction per grid cell for the entire Arctic shows a strong increase in June, reaching a maximum of 15 % by the end of June. The zonal mean of melt pond fractions indicates a dependence of the temporal development of melt ponds on the geographical latitude, and has its maximum in mid-July at latitudes between 80° and 88° N.

    Furthermore, the MODIS results are used to estimate the influence of melt ponds on retrievals of sea ice concentrations from passive microwave data. Results from a case study comparing sea ice concentrations from ARTIST Sea Ice-, NASA Team 2-, and Bootstrap-algorithms with MODIS sea ice concentrations indicate an underestimation of around 40 % for sea ice concentrations retrieved with microwave

  13. Penetrating Shortwave Radiation and Sea Ice Algae feedbacks using the Community Earth System Model

    Science.gov (United States)

    Arntsen, A. E.; Perovich, D. K.; Bailey, D. A.; Holland, M. M.

    2017-12-01

    Transmittance of solar radiation through the sea ice cover determines energy transfer to the upper ocean in the form of heat as well as photosynthetically active radiation (PAR) available for the growth of under ice phytoplankton and bottom ice algal communities. A thinning ice cover, increased pond coverage, and earlier melt onset has increased light availability to the upper ocean in contemporary Arctic ice-covered waters. To investigate seasonal and spatial variability of solar shortwave irradiance penetrating the ice cover in the Beaufort and Chukchi Sea regions, we use the fully coupled Community Earth System Model (CESM) in conjunction with a multistream radiative transfer model constrained and initiated by in situ observations. Results inform the importance of light attenuation by ice-based algal pigments within large scale global climate models. We demonstrate the presence of bio-optical feedbacks related to a younger ice cover and examine how these relationships are impacting the trajectory of under ice blooms and the energy budget of the ice-ocean system.

  14. Sea Lion Diet Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — California sea lions pup and breed at four of the nine Channel Islands in southern California. Since 1981, SWFSC MMTD has been conducting a diet study of sea lions...

  15. The Timing of Arctic Sea Ice Advance and Retreat as an Indicator of Ice-Dependent Marine Mammal Habitat

    Science.gov (United States)

    Stern, H. L.; Laidre, K. L.

    2013-12-01

    The Arctic is widely recognized as the front line of climate change. Arctic air temperature is rising at twice the global average rate, and the sea-ice cover is shrinking and thinning, with total disappearance of summer sea ice projected to occur in a matter of decades. Arctic marine mammals such as polar bears, seals, walruses, belugas, narwhals, and bowhead whales depend on the sea-ice cover as an integral part of their existence. While the downward trend in sea-ice extent in a given month is an often-used metric for quantifying physical changes in the ice cover, it is not the most relevant measure for characterizing changes in the sea-ice habitat of marine mammals. Species that depend on sea ice are behaviorally tied to the annual retreat of sea ice in the spring and advance in the fall. Changes in the timing of the spring retreat and the fall advance are more relevant to Arctic marine species than changes in the areal sea-ice coverage in a particular month of the year. Many ecologically important regions of the Arctic are essentially ice-covered in winter and ice-free in summer, and will probably remain so for a long time into the future. But the dates of sea-ice retreat in spring and advance in fall are key indicators of climate change for ice-dependent marine mammals. We use daily sea-ice concentration data derived from satellite passive microwave sensors to calculate the dates of sea-ice retreat in spring and advance in fall in 12 regions of the Arctic for each year from 1979 through 2013. The regions include the peripheral seas around the Arctic Ocean (Beaufort, Chukchi, East Siberian, Laptev, Kara, Barents), the Canadian Arctic Archipelago, and the marginal seas (Okhotsk, Bering, East Greenland, Baffin Bay, Hudson Bay). We find that in 11 of the 12 regions (all except the Bering Sea), sea ice is retreating earlier in spring and advancing later in fall. Rates of spring retreat range from -5 to -8 days/decade, and rates of fall advance range from +5 to +9

  16. Underway meteorological, navigational, physical and time series data collected aboard NOAA Ship Rainier in the Beaufort Sea, Bering Sea and others from 2015-06-19 to 2015-08-27 (NCEI Accession 0130918)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0130918 contains raw underway meteorological, navigational, physical and time series data logged by the Scientific Computer System (SCS) aboard NOAA...

  17. Underway meteorological, navigational, physical and time series data collected aboard NOAA Ship Fairweather in the Beaufort Sea, Bering Sea and others from 2015-06-12 to 2015-08-14 (NCEI Accession 0131828)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0131828 contains raw underway meteorological, navigational, physical and time series data logged by the Scientific Computer System (SCS) aboard NOAA...

  18. Quantifying the Bering Strait Oceanic Fluxes and their Impacts on Sea-Ice and Water Properties in the Chukchi and Beaufort Seas and Western Arctic Ocean for 2013-2014

    Science.gov (United States)

    2016-07-27

    R.Woodgate (2015), Arctic Freshwater Export: Status, Mechanisms, and Prospects, Global & Planetary Change , 125(0), 13-35, doi: 10.1016/j.gloplacha...causes and consequences of changes in the flow on the subarctic and Arctic system and beyond; and - provide annually updated estimates of these...quantities to the research community and the general public for related regional, arctic, and global studies, e.g., for other ONR-supported Arctic

  19. Synoptic measurements of subsurface phytoplankton layers collected from Fish Lidar, Oceanic, Experimenta (FLOE) Light Detection and Ranging (LIDAR) from aircraft in Chukchi Sea and Beaufort Sea from 2014-07-17 to 2014-07-29 (NCEI Accession 0128217)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In July 2014, FLOE was installed in a NOAA Twin Otter to make the first synoptic measurements of subsurface phytoplankton layers associated with the retreating ice...

  20. Productivity, chlorophyll a, Photosynthetically Active Radiation (PAR) and other phytoplankton data from the Arctic Ocean, Bering Sea, Chukchi Sea, Beaufort Sea, East Siberian Sea, Kara Sea, Barents Sea, and Arctic Archipelago measured between 17 April, 1954 and 30 May, 2006 compiled as part of the Arctic System Science Primary Production (ARCSS-PP) observational synthesis project (NODC Accession 0063065)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Arctic Ocean primary production data were assembled from original input data archived in various international databases, provided by individual investigators or in...

  1. The North Sea

    NARCIS (Netherlands)

    Cohen, K.M.; Westley, K.; Erkens, G.; Hijma, M.P.; Weerts, H.J.T.

    Chapter 7 in the 'SPLASHCOS Taphonomy book', on the landscape-archaeological inventory of the North Sea as a regional sea (covering British, Dutch, Belgian, German and Danish sectors of the southern and central North Sea). Abstract: This chapter gives a general overview of knowledge regarding the

  2. Sea level rise

    NARCIS (Netherlands)

    Warrick, R.A.; Oerlemans, J.

    1990-01-01

    This Section addresses three questions: Has global-mean sea level been rising during the last 100 years? What are the causal factors that could explain a past rise in sea level? And what increases in sea level can be expected in the future?

  3. Oceanography of marginal seas

    Digital Repository Service at National Institute of Oceanography (India)

    DileepKumar, M.

    The North Indian Ocean consists of three marginal seas; The Persian Gulf and the Red Sea in the west and the Andaman Sea in the east. Oceanographic features of these semi-enclosed basins have been discussed in this article. While circulation...

  4. The relation between Arctic sea ice surface elevation and draft: A case study using coincident AUV sonar and airborne scanning laser

    DEFF Research Database (Denmark)

    Doble, Martin J.; Skourup, Henriette; Wadhams, Peter

    2011-01-01

    Data are presented from a survey by airborne scanning laser profilometer and an AUV-mounted, upward looking swath sonar in the spring Beaufort Sea. The air-snow (surface elevation) and water-ice (draft) surfaces were mapped at 1 x 1 m resolution over a 300 x 300 m area. Data were separated...... into level and deformed ice fractions using the surface roughness of the sonar data. The relation (R = d/f) between draft, d, and surface elevation, f, was then examined. Correlation between top and bottom surfaces was essentially zero at full resolution, requiring averaging over patches of at least 11 m...... diameter to constrain the relation largely because of the significant error (similar to 15 cm) of the laser instrument. Level ice points were concentrated in two core regions, corresponding to level FY ice and refrozen leads, with variations in R attributed primarily to positive snow thickness variability...

  5. Increased Arctic sea ice drift alters adult female polar bear movements and energetics.

    Science.gov (United States)

    Durner, George M; Douglas, David C; Albeke, Shannon E; Whiteman, John P; Amstrup, Steven C; Richardson, Evan; Wilson, Ryan R; Ben-David, Merav

    2017-09-01

    Recent reductions in thickness and extent have increased drift rates of Arctic sea ice. Increased ice drift could significantly affect the movements and the energy balance of polar bears (Ursus maritimus) which forage, nearly exclusively, on this substrate. We used radio-tracking and ice drift data to quantify the influence of increased drift on bear movements, and we modeled the consequences for energy demands of adult females in the Beaufort and Chukchi seas during two periods with different sea ice characteristics. Westward and northward drift of the sea ice used by polar bears in both regions increased between 1987-1998 and 1999-2013. To remain within their home ranges, polar bears responded to the higher westward ice drift with greater eastward movements, while their movements north in the spring and south in fall were frequently aided by ice motion. To compensate for more rapid westward ice drift in recent years, polar bears covered greater daily distances either by increasing their time spent active (7.6%-9.6%) or by increasing their travel speed (8.5%-8.9%). This increased their calculated annual energy expenditure by 1.8%-3.6% (depending on region and reproductive status), a cost that could be met by capturing an additional 1-3 seals/year. Polar bears selected similar habitats in both periods, indicating that faster drift did not alter habitat preferences. Compounding reduced foraging opportunities that result from habitat loss; changes in ice drift, and associated activity increases, likely exacerbate the physiological stress experienced by polar bears in a warming Arctic. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  6. Spatial and temporal multiyear sea ice distributions in the Arctic: A neural network analysis of SSM/I data, 1988-2001

    Science.gov (United States)

    Belchansky, G.I.; Douglas, D.C.; Alpatsky, I.V.; Platonov, Nikita G.

    2004-01-01

    Arctic multiyear sea ice concentration maps for January 1988-2001 were generated from SSM/I brightness temperatures (19H, 19V, and 37V) using modified multiple layer perceptron neural networks. Learning data for the neural networks were extracted from ice maps derived from Okean and ERS satellite imagery to capitalize on the stability of active radar multiyear ice signatures. Evaluations of three learning algorithms and several topologies indicated that networks constructed with error back propagation learning and 3-20-1 topology produced the most consistent and physically plausible results. Operational neural networks were developed specifically with January learning data, and then used to estimate daily multiyear ice concentrations from daily-averaged SSM/I brightness temperatures during January. Monthly mean maps were produced for analysis by averaging the respective daily estimates. The 14-year series of January multiyear ice distributions revealed dense and persistent cover in the central Arctic surrounded by expansive regions of highly fluctuating interannual cover. Estimates of total multiyear ice area by the neural network were intermediate to those of other passive microwave algorithms, but annual fluctuations and trends were similar among all algorithms. When compared to Radarsat estimates of multiyear ice concentration in the Beaufort and Chukchi Seas (1997-1999), average discrepancies were small (0.9-2.5%) and spatial coherency was reasonable, indicating the neural network's Okean and ERS learning data facilitated passive microwave inversion that emulated backscatter signatures. During 1988-2001, total January multiyear ice area declined at a significant linear rate of -54.3 x 103 km2/yr-1 (-1.4%/yr-1). The most persistent and extensive decline in multiyear ice concentration (-3.3%/yr-1) occurred in the southern Beaufort and Chukchi Seas. In autumn 1996, a large multiyear ice recruitment of over 106 km2 (mostly in the Siberian Arctic) fully replenished

  7. a Novel Approach to Retrieve Arctic Sea Ice Thickness for Prediction and Analysis

    Science.gov (United States)

    Brucker, L.; Vernières, G.

    2017-12-01

    In spite of October-November Arctic-sea-ice-volume loss exceeding 7000 km3 in the decade following ICESat launch, most global ocean reanalysis systems are not able to reproduce such a drastic decline. Knowledge of the sea ice properties and its thickness distribution is critical to our understanding of polar ocean processes and the role of the polar regions in the Earth's climate system. Existing large-scale sea ice thickness datasets are derived from freeboard observations made by different satellite altimeters (radar and lidar). These datasets are significantly different due to the remote sensing technique and spacecraft orbit, and they are limited in time. These differences increase the difficulty of using such data for sea ice initialization and assimilation, and increase the challenge for studying sea ice processes and interactions with the ocean and atmosphere. For the first time, we were able to reproduce the Arctic sea ice thickness field at 10 km resolution with success for fall, winter, and spring (April/May depending on melt conditions) from passive microwave data. Our results reveal the same patterns of thickness distribution in the Arctic basin and peripheral seas as CryoSat-2, and the majority of the retrievals are within 0.5 m of CryoSat-2. The range of CryoSat-2 ice thickness is correctly retrieved, including in the upper range (3-5 m). The amplitude is well reproduced too, as the distribution of differences is centered on 0 m (no bias). Some underestimations are visible between islands of the Canadian Archipelago, but due to the size of the field of view our confidence will always be lower in this region where there is land contamination. An initial comparison of the AMSR2 ice thickness with IceBridge airborne products in different sectors (Beaufort sea, central Arctic) demonstrates the quality of the retrievals. In this presentation, we will also quantify the prediction and nowcast gain obtained from assimilating these new retrievals. We carried

  8. Sea level report

    International Nuclear Information System (INIS)

    Schwartz, M.L.

    1979-01-01

    Study of Cenozoic Era sea levels shows a continual lowering of sea level through the Tertiary Period. This overall drop in sea level accompanied the Pleistocene Epoch glacio-eustatic fluctuations. The considerable change of Pleistocene Epoch sea level is most directly attributable to the glacio-eustatic factor, with a time span of 10 5 years and an amplitude or range of approximately 200 m. The lowering of sea level since the end of the Cretaceous Period is attributed to subsidence and mid-ocean ridges. The maximum rate for sea level change is 4 cm/y. At present, mean sea level is rising at about 3 to 4 mm/y. Glacio-eustacy and tectono-eustacy are the parameters for predicting sea level changes in the next 1 my. Glacio-eustatic sea level changes may be projected on the basis of the Milankovitch Theory. Predictions about tectono-eustatic sea level changes, however, involve predictions about future tectonic activity and are therefore somewhat difficult to make. Coastal erosion and sedimentation are affected by changes in sea level. Erosion rates for soft sediments may be as much as 50 m/y. The maximum sedimentation accumulation rate is 20 m/100 y

  9. Salish Sea Genetics - Salish Sea genetic inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Salish Sea comprises most of the Puget Sound water area. Marine species are generally assemblages of discrete populations occupying various ecological niches....

  10. Pelagic sea snakes dehydrate at sea

    OpenAIRE

    Lillywhite, Harvey B.; Sheehy, Coleman M.; Brischoux, François; Grech, Alana

    2014-01-01

    Secondarily marine vertebrates are thought to live independently of fresh water. Here, we demonstrate a paradigm shift for the widely distributed pelagic sea snake, Hydrophis (Pelamis) platurus, which dehydrates at sea and spends a significant part of its life in a dehydrated state corresponding to seasonal drought. Snakes that are captured following prolonged periods without rainfall have lower body water content, lower body condition and increased tendencies to drink fresh water than do sna...

  11. Is ice-rafted sediment in a North Pole marine record evidence for perennial sea-ice cover?

    Science.gov (United States)

    Tremblay, L B; Schmidt, G A; Pfirman, S; Newton, R; DeRepentigny, P

    2015-10-13

    Ice-rafted sediments of Eurasian and North American origin are found consistently in the upper part (13 Ma BP to present) of the Arctic Coring Expedition (ACEX) ocean core from the Lomonosov Ridge, near the North Pole (≈88° N). Based on modern sea-ice drift trajectories and speeds, this has been taken as evidence of the presence of a perennial sea-ice cover in the Arctic Ocean from the middle Miocene onwards (Krylov et al. 2008 Paleoceanography 23, PA1S06. (doi:10.1029/2007PA001497); Darby 2008 Paleoceanography 23, PA1S07. (doi:10.1029/2007PA001479)). However, other high latitude land and marine records indicate a long-term trend towards cooling broken by periods of extensive warming suggestive of a seasonally ice-free Arctic between the Miocene and the present (Polyak et al. 2010 Quaternary Science Reviews 29, 1757-1778. (doi:10.1016/j.quascirev.2010.02.010)). We use a coupled sea-ice slab-ocean model including sediment transport tracers to map the spatial distribution of ice-rafted deposits in the Arctic Ocean. We use 6 hourly wind forcing and surface heat fluxes for two different climates: one with a perennial sea-ice cover similar to that of the present day and one with seasonally ice-free conditions, similar to that simulated in future projections. Model results confirm that in the present-day climate, sea ice takes more than 1 year to transport sediment from all its peripheral seas to the North Pole. However, in a warmer climate, sea-ice speeds are significantly faster (for the same wind forcing) and can deposit sediments of Laptev, East Siberian and perhaps also Beaufort Sea origin at the North Pole. This is primarily because of the fact that sea-ice interactions are much weaker with a thinner ice cover and there is less resistance to drift. We conclude that the presence of ice-rafted sediment of Eurasian and North American origin at the North Pole does not imply a perennial sea-ice cover in the Arctic Ocean, reconciling the ACEX ocean core data with

  12. Arctic Sea Level Reconstruction

    DEFF Research Database (Denmark)

    Svendsen, Peter Limkilde

    Reconstruction of historical Arctic sea level is very difficult due to the limited coverage and quality of tide gauge and altimetry data in the area. This thesis addresses many of these issues, and discusses strategies to help achieve a stable and plausible reconstruction of Arctic sea level from...... 1950 to today.The primary record of historical sea level, on the order of several decades to a few centuries, is tide gauges. Tide gauge records from around the world are collected in the Permanent Service for Mean Sea Level (PSMSL) database, and includes data along the Arctic coasts. A reasonable...... amount of data is available along the Norwegian and Russian coasts since 1950, and most published research on Arctic sea level extends cautiously from these areas. Very little tide gauge data is available elsewhere in the Arctic, and records of a length of several decades,as generally recommended for sea-level...

  13. Aminostratigraphic correlations and paleotemperature implications, Pliocene-Pleistocene high-sea-level deposits, northwestern Alaska

    Science.gov (United States)

    Kaufman, Darrell S.; Brigham-Grette, Julie

    Multiple periods of Late Pliocene and Pleistocene high sea level are recorded by surficial deposits along the coastal plains of northwestern Alaska. Analyses of the extent of amino acid epimerization in fossil molluscan shells from the Nome coastal plain of the northern Bering Sea coast, and from the Alaskan Arctic Coastal Plain of the Chukchi and Beaufort Sea coasts, allow recognition of at least five intervals of higher-than-present relative sea level. Three Late Pliocene transgressions are represented at Nome by the complex and protracted Beringian transgression, and on the Arctic Coastal Plain by the Colvillian, Bigbendian, and Fishcreekian transgressions. These were followed by a lengthy period of non-marine deposition during the Early Pleistocene when sea level did not reach above its present position. A Middle Pleistocene high-sea-level event is represented at Nome by the Anvilian transgression, and on the Arctic Coastal Plain by the Wainwrightian transgression. Anvilian deposits at the type locality are considerably younger than previously thought, perhaps as young as Oxygen-Isotope Stage 11 (˜410,000 BP). Finally, the last interglacial Pelukian transgression is represented discontinuously along the shores of northwestern Alaska. Amino acid epimerization data, together with previous paleomagnetic measurements, radiometric-age determinations, and paleontologic evidence provide geochronological constraints on the sequence of marine deposits. They form the basis of regional correlations and offer a means of evaluating the post-depositional thermal history of the high-sea-level deposits. Provisional correlations between marine units at Nome and the Artic Coastal Plain indicate that the temperature difference that separates the two sites today had existed by about 3.0 Ma. Since that time, the effective diagenetic temperature was lowered by about 3-4°C at both sites, and the mean annual temperature was lowered considerably more. This temperature decrease was

  14. SEA and planning

    DEFF Research Database (Denmark)

    Stoeglehner, G.; Brown, A.L.; Kørnøv, Lone

    2009-01-01

    As the field of strategic environmental assessment (SEA) has matured, the focus has moved from the development of legislation, guidelines and methodologies towards improving the effectiveness of SEA. Measuring and of course achieving effectiveness is both complex and challenging. This paper......, and the relationship of the SEA to the planning activity itself. This paper focuses on the influence that planners have in these implementation processes, postulating the hypothesis that these are key players in achieving effectiveness in SEA. Based upon implementation theory and empirical experience, the paper...

  15. Local Effects of Ice Floes on Skin Sea Surface Temperature in the Marginal Ice Zone from UAVs

    Science.gov (United States)

    Zappa, C. J.; Brown, S.; Emery, W. J.; Adler, J.; Wick, G. A.; Steele, M.; Palo, S. E.; Walker, G.; Maslanik, J. A.

    2013-12-01

    Recent years have seen extreme changes in the Arctic. Particularly striking are changes within the Pacific sector of the Arctic Ocean, and especially in the seas north of the Alaskan coast. These areas have experienced record warming, reduced sea ice extent, and loss of ice in areas that had been ice-covered throughout human memory. Even the oldest and thickest ice types have failed to survive through the summer melt period in areas such as the Beaufort Sea and Canada Basin, and fundamental changes in ocean conditions such as earlier phytoplankton blooms may be underway. Marginal ice zones (MIZ), or areas where the "ice-albedo feedback" driven by solar warming is highest and ice melt is extensive, may provide insights into the extent of these changes. Airborne remote sensing, in particular InfraRed (IR), offers a unique opportunity to observe physical processes at sea-ice margins. It permits monitoring the ice extent and coverage, as well as the ice and ocean temperature variability. It can also be used for derivation of surface flow field allowing investigation of turbulence and mixing at the ice-ocean interface. Here, we present measurements of visible and IR imagery of melting ice floes in the marginal ice zone north of Oliktok Point AK in the Beaufort Sea made during the Marginal Ice Zone Ocean and Ice Observations and Processes EXperiment (MIZOPEX) in July-August 2013. The visible and IR imagery were taken from the unmanned airborne vehicle (UAV) ScanEagle. The visible imagery clearly defines the scale of the ice floes. The IR imagery show distinct cooling of the skin sea surface temperature (SST) as well as a intricate circulation and mixing pattern that depends on the surface current, wind speed, and near-surface vertical temperature/salinity structure. Individual ice floes develop turbulent wakes as they drift and cause transient mixing of an influx of colder surface (fresh) melt water. The upstream side of the ice floe shows the coldest skin SST, and

  16. Pelagic sea snakes dehydrate at sea.

    Science.gov (United States)

    Lillywhite, Harvey B; Sheehy, Coleman M; Brischoux, François; Grech, Alana

    2014-05-07

    Secondarily marine vertebrates are thought to live independently of fresh water. Here, we demonstrate a paradigm shift for the widely distributed pelagic sea snake, Hydrophis (Pelamis) platurus, which dehydrates at sea and spends a significant part of its life in a dehydrated state corresponding to seasonal drought. Snakes that are captured following prolonged periods without rainfall have lower body water content, lower body condition and increased tendencies to drink fresh water than do snakes that are captured following seasonal periods of high rainfall. These animals do not drink seawater and must rehydrate by drinking from a freshwater lens that forms on the ocean surface during heavy precipitation. The new data based on field studies indicate unequivocally that this marine vertebrate dehydrates at sea where individuals may live in a dehydrated state for possibly six to seven months at a time. This information provides new insights for understanding water requirements of sea snakes, reasons for recent declines and extinctions of sea snakes and more accurate prediction for how changing patterns of precipitation might affect these and other secondarily marine vertebrates living in tropical oceans.

  17. Pelagic sea snakes dehydrate at sea

    Science.gov (United States)

    Lillywhite, Harvey B.; Sheehy, Coleman M.; Brischoux, François; Grech, Alana

    2014-01-01

    Secondarily marine vertebrates are thought to live independently of fresh water. Here, we demonstrate a paradigm shift for the widely distributed pelagic sea snake, Hydrophis (Pelamis) platurus, which dehydrates at sea and spends a significant part of its life in a dehydrated state corresponding to seasonal drought. Snakes that are captured following prolonged periods without rainfall have lower body water content, lower body condition and increased tendencies to drink fresh water than do snakes that are captured following seasonal periods of high rainfall. These animals do not drink seawater and must rehydrate by drinking from a freshwater lens that forms on the ocean surface during heavy precipitation. The new data based on field studies indicate unequivocally that this marine vertebrate dehydrates at sea where individuals may live in a dehydrated state for possibly six to seven months at a time. This information provides new insights for understanding water requirements of sea snakes, reasons for recent declines and extinctions of sea snakes and more accurate prediction for how changing patterns of precipitation might affect these and other secondarily marine vertebrates living in tropical oceans. PMID:24648228

  18. Sea Ice and Ice Temperature Variability as Observed by Microwave and Infrared Satellite Data

    Science.gov (United States)

    Comiso, Josefino C.; Koblinsky, Chester J. (Technical Monitor)

    2001-01-01

    Recent reports of a retreating and thinning sea ice cover in the Arctic have pointed to a strong suggestion of significant warming in the polar regions. It is especially important to understand what these reports mean in light of the observed global warning and because the polar regions are expected to be most sensitive to changes in climate. To gain insight into this phenomenon, co-registered ice concentrations and surface temperatures derived from two decades of satellite microwave and infrared data have been processed and analyzed. While observations from meteorological stations indicate consistent surface warming in both regions during the last fifty years, the last 20 years of the same data set show warming in the Arctic but a slight cooling in the Antarctic. These results are consistent with the retreat in the Arctic ice cover and the advance in the Antarctic ice cover as revealed by historical satellite passive microwave data. Surface temperatures derived from satellite infrared data are shown to be consistent within 3 K with surface temperature data from the limited number of stations. While not as accurate, the former provides spatially detailed changes over the twenty year period. In the Arctic, for example, much of the warming occurred in the Beaufort Sea and the North American region in 1998 while slight cooling actually happened in parts of the Laptev Sea and Northern Siberia during the same time period. Big warming anomalies are also observed during the last five years but a periodic cycle of about ten years is apparent suggesting a possible influence of the North Atlantic Oscillation. In the Antarctic, large interannual and seasonal changes are also observed in the circumpolar ice cover with regional changes showing good coherence with surface temperature anomalies. However, a mode 3 is observed to be more dominant than the mode 2 wave reported in the literature. Some of these spatial and temporal changes appear to be influenced by the Antarctic

  19. Sea Ice Index, Version 3

    Data.gov (United States)

    National Aeronautics and Space Administration — The Sea Ice Index provides a quick look at Arctic- and Antarctic-wide changes in sea ice. It is a source for consistent, up-to-date sea ice extent and concentration...

  20. Sea surface temperatures and salinities from platforms in the Barents Sea, Sea of Japan, North Atlantic Ocean, Philippine Sea, Red Sea, and the South China Sea (Nan Hai) from 1896-1950 (NODC Accession 0000506)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Surface temperatures and salinities were collected in the Barents Sea, Sea of Japan, North Atlantic Ocean, Philippine Sea, Red Sea, and South China Sea (Nan Hai)...

  1. Air Sea Rescue

    Science.gov (United States)

    1942-01-01

    and are then able to nake land and do not ditch the aircraft, make certain that Air/Sea rescue service is notified of this as soon as possible...the 4i r ’’ S * a Rescue Service . d. Khen the pilot considers it unlikely that he will reach the coast, and yet a descent into the sea is not

  2. Waves in the seas

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    Not all sea waves look alike in form. Scientists, in fact, classify all waves into definite groups, which can be simulated on a computer using specific models. Thus there are many types of wave forms on the sea surface like regular sinusoidal waves...

  3. Dilemmas in SEA application

    DEFF Research Database (Denmark)

    Lyhne, Ivar

    Dilemmas in SEA Application: The DK Energy SectorIvar Lyhne - lyhne@plan.aau.dk. Based on three years of collaborative research, this paper outlines dilemmas in the application of SEA in the strategic development of the Danish energy sector. The dilemmas are based on concrete examples from practice...

  4. Indicators and SEA

    DEFF Research Database (Denmark)

    Gao, Jingjing; Kørnøv, Lone; Christensen, Per

    Abstract: Indicators are widely used in SEA to measure, communicate and monitor impacts from a proposed policy, plan or programme, and can improve the effectiveness for the SEA by simplifying the complexity of both assessment and presentation. Indicators can be seen as part of the implementation...... process helping to understand, communicate and, integrate important environmental issues in planning and decision-making. On the other hand, use of indicators can also limit SEA effectiveness, if the ones chosen are biased or limited, if the aggregation gives incorrect interpretation...... and if the information requirement for different target groups is not addressed. Indicators are widely used in SEA to measure, communicate and monitor impacts from a proposed policy, plan or programme, and can improve the effectiveness for the SEA by simplifying the complexity of both assessment and presentation...

  5. Observation of pressure ridges in SAR images of sea ice: Scattering theory and comparison with observations

    Science.gov (United States)

    Vesecky, J. F.; Daida, J. M.; Shuchman, R. A.; Onstott, R. H.; Camiso, J. C.

    1993-01-01

    both the quasi-specular and Bragg resonant scatter mechanisms. This model is extended to include contributions from volume scatter and scatter from discrete objects. Geometrical characteristics from the AOL survey and model calculations imply that for radar wavelengths and observation geometries that are dominated by the quasi-specular scattering mechanism radar backscatter from a ridge is a measure of peak ridge height. We present scattering model results and compare them with ridges observed during the LEADEX experiment of March-April 1992 when both X, C, and L-band aircraft SAR and the ERS-1 satellite SAR observed a region in the Beaufort Sea near 86 deg N, 10 deg W. Data were also collected documenting ridge characteristics on the surface. The surface data are used to generate a SAR signature via the scattering model described above. The predicted SAR signatures compare well with the SAR observations.

  6. C-band Joint Active/Passive Dual Polarization Sea Ice Detection

    Science.gov (United States)

    Keller, M. R.; Gifford, C. M.; Winstead, N. S.; Walton, W. C.; Dietz, J. E.

    2017-12-01

    A technique for synergistically-combining high-resolution SAR returns with like-frequency passive microwave emissions to detect thin (standard deviation to mean) has fewer ambiguities between ice and water than cross sections, but breaking waves still produce ice-like signatures for both polarizations. For the radiometer, the PRIC (polarization ratio ice concentration) identifies areas that are unambiguously water. Applying cumulative statistics to co-located COV levels adaptively determines an ice/water threshold. Outcomes from extensive testing with Sentinel and AMSR-2 data are shown in the results. The detection algorithm was applied to the freeze-up in the Beaufort, Chukchi, Barents, and East Siberian Seas in 2015 and 2016, spanning mid-September to early November of both years. At the end of the melt, 6 GHz PRIC values are 5-10% greater than those reported by radiometric algorithms at 19 and 37 GHz. During freeze-up, COV separates grease ice (concentrations than operational scatterometer or radiometer algorithms, mostly from ice edge and coastal areas. In conclusion, the algorithm presented combines high-resolution SAR returns with passive microwave emissions for automated ice detection at SAR resolutions.

  7. Field and Satellite Observations of the Formation and Distribution of Arctic Atmospheric Bromine Above a Rejuvenated Sea Ice Cover

    Science.gov (United States)

    Nghiem, Son V.; Rigor, Ignatius G.; Richter, Andreas; Burrows, John P.; Shepson, Paul B.; Bottenheim, Jan; Barber, David G.; Steffen, Alexandra; Latonas, Jeff; Wang, Feiyue; hide

    2012-01-01

    Recent drastic reduction of the older perennial sea ice in the Arctic Ocean has resulted in a vast expansion of younger and saltier seasonal sea ice. This increase in the salinity of the overall ice cover could impact tropospheric chemical processes. Springtime perennial ice extent in 2008 and 2009 broke the half-century record minimum in 2007 by about one million km2. In both years seasonal ice was dominant across the Beaufort Sea extending to the Amundsen Gulf, where significant field and satellite observations of sea ice, temperature, and atmospheric chemicals have been made. Measurements at the site of the Canadian Coast Guard Ship Amundsen ice breaker in the Amundsen Gulf showed events of increased bromine monoxide (BrO), coupled with decreases of ozone (O3) and gaseous elemental mercury (GEM), during cold periods in March 2008. The timing of the main event of BrO, O3, and GEM changes was found to be consistent with BrO observed by satellites over an extensive area around the site. Furthermore, satellite sensors detected a doubling of atmospheric BrO in a vortex associated with a spiral rising air pattern. In spring 2009, excessive and widespread bromine explosions occurred in the same region while the regional air temperature was low and the extent of perennial ice was significantly reduced compared to the case in 2008. Using satellite observations together with a Rising-Air-Parcel model, we discover a topographic control on BrO distribution such that the Alaskan North Slope and the Canadian Shield region were exposed to elevated BrO, whereas the surrounding mountains isolated the Alaskan interior from bromine intrusion.

  8. South Polar Skua breeding populations in the Ross Sea assessed from demonstrated relationship with Adélie Penguin numbers

    Science.gov (United States)

    Wilson, Deborah J.; Lyver, Phil O'B.; Greene, Terry C.; Whitehead, Amy L.; Dugger, Catherine; Karl, Brian J.; Barringer, James R. F.; McGarry, Roger; Pollard, Annie M.; Ainley, David G.

    2017-01-01

    In the Ross Sea region, most South Polar Skuas (Stercorarius maccormicki) nest near Adélie Penguin (Pygoscelis adeliae) colonies, preying and scavenging on fish, penguins, and other carrion. To derive a relationship to predict skua numbers from better-quantified penguin numbers, we used distance sampling to estimate breeding skua numbers within 1000 m of 5 penguin nesting locations (Cape Crozier, Cape Royds, and 3 Cape Bird locations) on Ross Island in 3 consecutive years. Estimated numbers of skua breeding pairs were highest at Cape Crozier (270,000 penguin pairs; 1099 and 1347 skua pairs in 2 respective years) and lowest at Cape Royds (3000 penguin pairs; 45 skua pairs). The log–log linear relationship (R2 = 0.98) between pairs of skuas and penguins was highly significant, and most historical estimates of skua and penguin numbers in the Ross Sea were within 95 % prediction intervals of the regression. Applying our regression model to current Adélie Penguin colony sizes at 23 western Ross Sea locations predicted that 4635 pairs of skuas now breed within 1000 m of penguin colonies in the Ross Island metapopulation (including Beaufort Island) and northern Victoria Land. We estimate, using published skua estimates for elsewhere in Antarctica, that the Ross Sea South Polar Skua population comprises ~50 % of the world total, although this may be an overestimate because of incomplete data elsewhere. To improve predictions and enable measurement of future skua population change, we recommend additional South Polar Skua surveys using consistent distance-sampling methods at penguin colonies of a range of sizes.

  9. Sea Perch Project

    Science.gov (United States)

    2010-01-01

    David Lalejini, an employee of the Naval Research Laboratory at NASA's John C. Stennis Space Center, helps a pair of teachers deploy a remotely-operated underwater Sea Perch robot during workshop activities Dec. 11. The Stennis Education Office teamed with Naval Research Laboratory counterparts to conduct a two-day workshop Dec. 10-11 for Louisiana and Mississippi teachers. During the no-cost workshop, teachers learned to build and operate Sea Perch robots. The teachers now can take the Sea Perch Program back to students.

  10. Caspian sea: petroleum challenges

    International Nuclear Information System (INIS)

    2005-01-01

    The Caspian sea is one of the world areas the most promising in terms of investments and petroleum development. This study presents the petroleum challenges generated by this hydrocarbons reserve. The first part discusses the juridical status (sea or lake), the petroleum and the gas reserves, the ecosystem and the today environment (fishing and caviar), the geostrategic situation and the transport of gas and oil. It provides also a chronology from 1729 to 2005, a selection of Internet sites, books and reports on the subject and identity sheets of the countries around the Caspian sea. (A.L.B.)

  11. Numerical investigation of the Arctic ice-ocean boundary layer and implications for air-sea gas fluxes

    Science.gov (United States)

    Bigdeli, Arash; Loose, Brice; Nguyen, An T.; Cole, Sylvia T.

    2017-01-01

    In ice-covered regions it is challenging to determine constituent budgets - for heat and momentum, but also for biologically and climatically active gases like carbon dioxide and methane. The harsh environment and relative data scarcity make it difficult to characterize even the physical properties of the ocean surface. Here, we sought to evaluate if numerical model output helps us to better estimate the physical forcing that drives the air-sea gas exchange rate (k) in sea ice zones. We used the budget of radioactive 222Rn in the mixed layer to illustrate the effect that sea ice forcing has on gas budgets and air-sea gas exchange. Appropriate constraint of the 222Rn budget requires estimates of sea ice velocity, concentration, mixed-layer depth, and water velocities, as well as their evolution in time and space along the Lagrangian drift track of a mixed-layer water parcel. We used 36, 9 and 2 km horizontal resolution of regional Massachusetts Institute of Technology general circulation model (MITgcm) configuration with fine vertical spacing to evaluate the capability of the model to reproduce these parameters. We then compared the model results to existing field data including satellite, moorings and ice-tethered profilers. We found that mode sea ice coverage agrees with satellite-derived observation 88 to 98 % of the time when averaged over the Beaufort Gyre, and model sea ice speeds have 82 % correlation with observations. The model demonstrated the capacity to capture the broad trends in the mixed layer, although with a significant bias. Model water velocities showed only 29 % correlation with point-wise in situ data. This correlation remained low in all three model resolution simulations and we argued that is largely due to the quality of the input atmospheric forcing. Overall, we found that even the coarse-resolution model can make a modest contribution to gas exchange parameterization, by resolving the time variation of parameters that drive the 222Rn budget

  12. Variability and trends in the Arctic Sea ice cover: Results from different techniques

    Science.gov (United States)

    Comiso, Josefino C.; Meier, Walter N.; Gersten, Robert

    2017-08-01

    Variability and trend studies of sea ice in the Arctic have been conducted using products derived from the same raw passive microwave data but by different groups using different algorithms. This study provides consistency assessment of four of the leading products, namely, Goddard Bootstrap (SB2), Goddard NASA Team (NT1), EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI-SAF 1.2), and Hadley HadISST 2.2 data in evaluating variability and trends in the Arctic sea ice cover. All four provide generally similar ice patterns but significant disagreements in ice concentration distributions especially in the marginal ice zone and adjacent regions in winter and meltponded areas in summer. The discrepancies are primarily due to different ways the four techniques account for occurrences of new ice and meltponding. However, results show that the different products generally provide consistent and similar representation of the state of the Arctic sea ice cover. Hadley and NT1 data usually provide the highest and lowest monthly ice extents, respectively. The Hadley data also show the lowest trends in ice extent and ice area at -3.88%/decade and -4.37%/decade, respectively, compared to an average of -4.36%/decade and -4.57%/decade for all four. Trend maps also show similar spatial distribution for all four with the largest negative trends occurring at the Kara/Barents Sea and Beaufort Sea regions, where sea ice has been retreating the fastest. The good agreement of the trends especially with updated data provides strong confidence in the quantification of the rate of decline in the Arctic sea ice cover.Plain Language SummaryThe declining Arctic sea ice cover, especially in the summer, has been the center of attention in recent years. Reports on the sea ice cover have been provided by different institutions using basically the same set of satellite data but different techniques for estimating key parameters such as ice concentration, ice extent, and ice area. In

  13. Black Sea aerosols

    International Nuclear Information System (INIS)

    Hacisalihoglu, G.; Eliyakut, F.; Anwari, M.A.; Ataman, O.Y.; Balkas, T.I.; Tuncel, G.; Olmez, I.

    1991-01-01

    Shipboard, high volume air particulate samples were collected from the Black Sea atmosphere and analyzed by instrumental neutron activation analysis, atomic absorption spectrophotometry and ion chromatography for about 40 elements and ions. Concentrations of elements in the eastern and western parts of the Black Sea are different at the 95% confidence level, with lower concentrations in the eastern Black Sea. Back-trajectories and concentrations of elements in trajectory groups show that Europe accounts for more than 70% of the anthropogenic elements in the atmosphere. The average sulfate concentration was 7 μg/m 3 , which is comparable with rural sulfate levels in western Europe. Fluxes of elements from the atmosphere to the Black Sea are in good agreement with the results of similar flux calculations for other regions

  14. Dead Sea Scrolls

    Science.gov (United States)

    1994-01-01

    A consortium of researchers from Jet Propulsion Laboratory and three other organizations used charged coupled devices (CCDs) and other imaging enhancement technology to decipher previously unreadable portions of the Dead Sea Scrolls. The technique has potentially important implications for archeology.

  15. Baltic Sea: Radionuclides

    DEFF Research Database (Denmark)

    Nielsen, Sven Poul; Lüning, Maria; Ilus, Erkki

    2011-01-01

    The most significant source of anthropogenic radioactivity in the Baltic Sea is fallout from the accident at the Chernobyl nuclear power plant in 1986. The second most important source is global fallout from atmospheric nuclear weapons tests carried out during the late 1950s and early 1960s....... Radioactivity inputs into the Baltic Sea from nuclear reprocessing plants in Western Europe have become of minor importance due to significant reduction of discharges in recent years. In terms of input of 137Cs into the Baltic Sea, Chernobyl fallout has contributed about 82% and nuclear weapons test fallout...... about 14%. For 90Sr in the Baltic Sea, input from atmospheric fallout from nuclear weapons tests has contributed about 81%, while the contribution from Chernobyl fallout was about 13%. Cesium-137 is the main indicator of Baltic seawater with respect to anthropogenic radioactivity. The highest...

  16. Baltic Sea: Radionuclides

    DEFF Research Database (Denmark)

    Nielsen, Sven Poul; Lüning, Maria; Ilus, Erkki

    2010-01-01

    The most significant source of anthropogenic radioactivity in the Baltic Sea is fallout from the accident at the Chernobyl nuclear power plant in 1986. The second most important source is global fallout from atmospheric nuclear weapons tests carried out during the late 1950s and early 1960s....... Radioactivity inputs into the Baltic Sea from nuclear reprocessing plants in Western Europe have become of minor importance due to significant reduction of discharges in recent years. In terms of input of 137Cs into the Baltic Sea, Chernobyl fallout has contributed about 82% and nuclear weapons test fallout...... about 14%. For 90Sr in the Baltic Sea, input from atmospheric fallout from nuclear weapons tests has contributed about 81%, while the contribution from Chernobyl fallout was about 13%. Cesium-137 is the main indicator of Baltic seawater with respect to anthropogenic radioactivity. The highest...

  17. Sea Ice Ecosystems

    Science.gov (United States)

    Arrigo, Kevin R.

    2014-01-01

    Polar sea ice is one of the largest ecosystems on Earth. The liquid brine fraction of the ice matrix is home to a diverse array of organisms, ranging from tiny archaea to larger fish and invertebrates. These organisms can tolerate high brine salinity and low temperature but do best when conditions are milder. Thriving ice algal communities, generally dominated by diatoms, live at the ice/water interface and in recently flooded surface and interior layers, especially during spring, when temperatures begin to rise. Although protists dominate the sea ice biomass, heterotrophic bacteria are also abundant. The sea ice ecosystem provides food for a host of animals, with crustaceans being the most conspicuous. Uneaten organic matter from the ice sinks through the water column and feeds benthic ecosystems. As sea ice extent declines, ice algae likely contribute a shrinking fraction of the total amount of organic matter produced in polar waters.

  18. Pollution of coastal seas

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    cities. Various types of wastes, if not properly treated, would cause serious pollution of these shallow seas endangering marine life and spoiling recreational facilities. Different polluting agents like sewage, chemicals, industrial coolants etc...

  19. Sea Scallop Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Sea Scallop Survey began in 1980 and has covered an area from Cape Hatteras to Georges Bank. The survey aims to determine the distribution and...

  20. South China Sea

    Science.gov (United States)

    Morton, Brian; Blackmore, Graham

    2001-01-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshop and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km2 and depths range from the shallowest coastal fringe to 5377 m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economies on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of the three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken on the South

  1. South China Sea

    Energy Technology Data Exchange (ETDEWEB)

    Morton, Brian [Hong Kong Univ., Swire Inst. of Marine Science, Hong Kong (China); Hong Kong Univ., Dept. of Ecology and Biodiversity, Hong Kong (China); Blackmore, Graham [Hong Kong Univ. of Science and Technology, Dept. of Biology, Hong Kong (China)

    2001-07-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshops and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km{sup 2} and depths range from the shallowest coastal fringe to 5377m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economics on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global total of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken

  2. Projecting future sea level

    Science.gov (United States)

    Cayan, Daniel R.; Bromirski, Peter; Hayhoe, Katharine; Tyree, Mary; Dettinger, Mike; Flick, Reinhard

    2006-01-01

    California’s coastal observations and global model projections indicate that California’s open coast and estuaries will experience increasing sea levels over the next century. Sea level rise has affected much of the coast of California, including the Southern California coast, the Central California open coast, and the San Francisco Bay and upper estuary. These trends, quantified from a small set of California tide gages, have ranged from 10–20 centimeters (cm) (3.9–7.9 inches) per century, quite similar to that estimated for global mean sea level. So far, there is little evidence that the rate of rise has accelerated, and the rate of rise at California tide gages has actually flattened since 1980, but projections suggest substantial sea level rise may occur over the next century. Climate change simulations project a substantial rate of global sea level rise over the next century due to thermal expansion as the oceans warm and runoff from melting land-based snow and ice accelerates. Sea level rise projected from the models increases with the amount of warming. Relative to sea levels in 2000, by the 2070–2099 period, sea level rise projections range from 11–54 cm (4.3–21 in) for simulations following the lower (B1) greenhouse gas (GHG) emissions scenario, from 14–61 cm (5.5–24 in) for the middle-upper (A2) emission scenario, and from 17–72 cm (6.7–28 in) for the highest (A1fi) scenario. In addition to relatively steady secular trends, sea levels along the California coast undergo shorter period variability above or below predicted tide levels and changes associated with long-term trends. These variations are caused by weather events and by seasonal to decadal climate fluctuations over the Pacific Ocean that in turn affect the Pacific coast. Highest coastal sea levels have occurred when winter storms and Pacific climate disturbances, such as El Niño, have coincided with high astronomical tides. This study considers a range of projected future

  3. Changes in extreme sea levels in the Baltic Sea

    Science.gov (United States)

    Dieterich, Christian; Gröger, Matthias; Andersson, Helén; Nerheim, Signild; Jönsson, Anette

    2016-04-01

    A newly developed shallow water model for the Baltic Sea and North Sea is presented. The model is validated by means of a comparison with hindcast simulations with observational data sets. The aim of the development is to provide and apply a modelling tool to model extreme sea levels in the Baltic Sea, Kattegat and Skagerrak. The model approach will support the direct analysis of extreme sea level observations in the past and provide the possibility to extend the statistical data base by producing very long time series or very large ensembles of coastal sea levels. This effort is intended to contribute to an assessment of risks due to storm surges and coastal flooding in the 21st century along the coast of Sweden. By using different RCP climate scenarios downscaled with a regional, coupled climate model atmospheric forcing is available to project possible changes in extreme sea levels into the future. Projected sea level rise, changes in dynamical sea level in the North East Atlantic and tidal forcing in the northern North Sea are applied as boundary condition which allows to investigate their impact on the dynamics of regional sea level variability. Initial experiments focus on the impact of model resolution, resolution in the atmospheric forcing and the amount of details necessary in the bathymetry to faithfully model coastal sea level in the Baltic Sea and North Sea.

  4. Affects of Changes in Sea Ice Cover on Bowhead Whales and Subsistence Whaling in the Western Arctic

    Science.gov (United States)

    Moore, S.; Suydam, R.; Overland, J.; Laidre, K.; George, J.; Demaster, D.

    2004-12-01

    Global warming may disproportionately affect Arctic marine mammals and disrupt traditional subsistence hunting activities. Based upon analyses of a 24-year time series (1979-2002) of satellite-derived sea ice cover, we identified significant positive trends in the amount of open-water in three large and five small-scale regions in the western Arctic, including habitats where bowhead whales (Balaena mysticetus) feed or are suspected to feed. Bowheads are the only mysticete whale endemic to the Arctic and a cultural keystone species for Native peoples from northwestern Alaska and Chukotka, Russia. While copepods (Calanus spp.) are a mainstay of the bowhead diet, prey sampling conducted in the offshore region of northern Chukotka and stomach contents from whales harvested offshore of the northern Alaskan coast indicate that euphausiids (Thysanoessa spp.) advected from the Bering Sea are also common prey in autumn. Early departure of sea ice has been posited to control availability of zooplankton in the southeastern Bering Sea and in the Cape Bathurst polynya in the southeastern Canadian Beaufort Sea, with maximum secondary production associated with a late phytoplankton bloom in insolatoin-stratified open water. While it is unclear if declining sea-ice has directly affected production or advection of bowhead prey, an extension of the open-water season increases opportunities for Native subsistence whaling in autumn. Therefore, bowhead whales may provide a nexus for simultaneous exploration of the effects sea ice reduction on pagophillic marine mammals and on the social systems of the subsistence hunting community in the western Arctic. The NOAA/Alaska Fisheries Science Center and NSB/Department of Wildlife Management will investigate bowhead whale stock identity, seasonal distribution and subsistence use patterns during the International Polar Year, as an extension of research planned for 2005-06. This research is in response to recommendations from the Scientific

  5. Winter sea ice export from the Laptev Sea preconditions the local summer sea ice cover

    Science.gov (United States)

    Krumpen, T.; Haas, C.; Itkin, P.

    2016-12-01

    Interannual variability and trends in sea ice export out of the Laptev Sea were investigated using a combination of observations and satellite data. The Laptev Sea shows a statistically positive trend in ice area export that is likely associated to an increase in ice drift velocity being the consequence of a thinning ice cover further north. Moreover, we could show that there is a high statistical connection of the late winter (Jan-May) sea ice export and ice formation in Laptev Sea polynyas to the summer sea ice concentration. By means of a sensitivity study using a coupled sea ice-ocean model (MITgcm), we could highlight the importance of winter sea ice processes for summer sea ice conditions in the Laptev Sea and likewise in the adjacent Siberian Seas. Years of high ice export have a thinning effect on the ice cover, which in turn preconditions early fast ice break up, pack ice melt and the occurrence of negative sea ice extent anomalies in summer. Our model simulation also indicate that observed increase in the sea ice export from the Laptev Sea is accompanied by an increase in the volume export, which is important for the Arctic sea ice budget.

  6. The Dead Sea

    Science.gov (United States)

    2006-01-01

    The Dead Sea is the lowest point on Earth at 418 meters below sea level, and also one of the saltiest bodies of water on Earth with a salinity of about 300 parts-per-thousand (nine times greater than ocean salinity). It is located on the border between Jordan and Israel, and is fed by the Jordan River. The Dead Sea is located in the Dead Sea Rift, formed as a result of the Arabian tectonic plate moving northward away from the African Plate. The mineral content of the Dead Sea is significantly different from that of ocean water, consisting of approximately 53% magnesium chloride, 37% potassium chloride and 8% sodium chloride. In the early part of the 20th century, the Dead Sea began to attract interest from chemists who deduced that the Sea was a natural deposit of potash and bromine. From the Dead Sea brine, Israel and Jordan produce 3.8 million tons potash, 200,000 tons elemental bromine, 45,000 tons caustic soda, 25, 000 tons magnesium metal, and sodium chloride. Both countries use extensive salt evaporation pans that have essentially diked the entire southern end of the Dead Sea. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining

  7. Barrier island response to an elevated sea-level anomaly: Onslow Beach, North Carolina, USA

    Science.gov (United States)

    Theuerkauf, E. J.; Rodriguez, A. B.; Fegley, S. R.; Luettich, R.

    2012-12-01

    Variations in sea level over time scales ranging from hours to millennia influence coastal processes and evolution. At annual time scales, elevated sea-level anomalies produce coastal flooding and promote beach erosion. This study examines the coastal response of Onslow Beach, North Carolina to the summer 2009 East Coast sea-level anomaly. Onslow Beach is a 12-km-long wave-dominated barrier island with highly variable along-barrier morphology. The transgressive southern portion of the island is characterized by a narrow beach, low dunes, and multiple washover fans, while the regressive northern portion is characterized by a wide beach and continuous tall dunes. Hourly tide gauge data from adjacent NOAA stations (Beaufort and Wrightsville Beach) are used to determine the timing and extent of elevated water levels. The seasonal and longer term trends (relative sea level rise) are removed from both of the water level series and the sea-level anomaly is represented by a large residual between the observed and predicted water levels. Beach response is quantified using terrestrial laser scanning for morphology and from geoprobe cores to determine the maximum depth of erosion (MDOE). The mean high water (MHW) shoreline and dune toe are digitized from digital elevation models derived from the laser scans and analyzed using the Digital Shoreline Analysis System (DSAS). Landward (negative) movement of these contacts indicates erosion. Wave data collected from an Acoustic Wave and Current Meter (AWAC) located offshore of the southern end of Onslow Beach is used to characterize the wave regime throughout the study. Water level is elevated in the tide gauge data from June 2009 to March 2010. This sea-level anomaly corresponds with an increase in the maximum depth of erosion between 2009 and 2010. Landward movement of the MHW shoreline and the dunetoe increased during the period between September 2009 and May 2010 indicating an increase in beach erosion during the sea

  8. Arctic Ocean outflow and glacier–ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland

    Directory of Open Access Journals (Sweden)

    I. A. Dmitrenko

    2017-12-01

    Full Text Available The first-ever conductivity–temperature–depth (CTD observations on the Wandel Sea shelf in northeastern Greenland were collected in April–May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014–2015 drift. The CTD profiles are used to reveal the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has interacted with the warm Atlantic water outflow through the Fram Strait, recorded below 140 m. Over the outer shelf, the halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient polar water mass across the continental slope. At the front of the tidewater glacier outlet, colder and turbid water intrusions were observed at the base of the halocline. On the temperature–salinity plots these stations indicate a mixing line that is different from the ambient water and seems to be conditioned by the ocean–glacier interaction. Our observations of Pacific water are set within the context of upstream observations in the Beaufort Sea and downstream observations from the Northeast Water Polynya, and clearly show the modification of Pacific water during its advection across the Arctic Ocean. Moreover, ambient water over the Wandel Sea slope shows different thermohaline structures indicating the different origin and pathways of the on-shore and off-shore branches of the Arctic Ocean outflow through the western Fram Strait.

  9. Arctic Ocean outflow and glacier-ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland)

    Science.gov (United States)

    Dmitrenko, Igor A.; Kirillov, Sergey A.; Rudels, Bert; Babb, David G.; Toudal Pedersen, Leif; Rysgaard, Søren; Kristoffersen, Yngve; Barber, David G.

    2017-12-01

    The first-ever conductivity-temperature-depth (CTD) observations on the Wandel Sea shelf in northeastern Greenland were collected in April-May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014-2015 drift. The CTD profiles are used to reveal the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has interacted with the warm Atlantic water outflow through the Fram Strait, recorded below 140 m. Over the outer shelf, the halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient polar water mass across the continental slope. At the front of the tidewater glacier outlet, colder and turbid water intrusions were observed at the base of the halocline. On the temperature-salinity plots these stations indicate a mixing line that is different from the ambient water and seems to be conditioned by the ocean-glacier interaction. Our observations of Pacific water are set within the context of upstream observations in the Beaufort Sea and downstream observations from the Northeast Water Polynya, and clearly show the modification of Pacific water during its advection across the Arctic Ocean. Moreover, ambient water over the Wandel Sea slope shows different thermohaline structures indicating the different origin and pathways of the on-shore and off-shore branches of the Arctic Ocean outflow through the western Fram Strait.

  10. Sea Spray Aerosols

    DEFF Research Database (Denmark)

    Butcher, Andrew Charles

    emissions produced directly from bubble bursting as the result of air entrainment from breaking waves and particles generated from secondary emissions of volatile organic compounds. In the first paper, we study the chemical properties of particles produced from several sea water proxies with the use...... of a cloud condensation nuclei ounter. Proxy solutions with high inorganic salt concentrations and some organics produce sea spray aerosol particles with little change in cloud condensation activity relative to pure salts. Comparison is made between a frit based method for bubble production and a plunging...... a relationship between plunging jet particle ux, oceanic particle ux, and energy dissipation rate in both systems. Previous sea spray aerosol studies dissipate an order of magnitude more energy for the same particle ux production as the open ocean. A scaling factor related to the energy expended in air...

  11. Caribbean Sea Level Network

    Science.gov (United States)

    von Hillebrandt-Andrade, C.; Crespo Jones, H.

    2012-12-01

    Over the past 500 years almost 100 tsunamis have been observed in the Caribbean and Western Atlantic, with at least 3510 people having lost their lives to this hazard since 1842. Furthermore, with the dramatic increase in population and infrastructure along the Caribbean coasts, today, millions of coastal residents, workers and visitors are vulnerable to tsunamis. The UNESCO IOC Intergovernmental Coordination Group for Tsunamis and other Coastal Hazards for the Caribbean and Adjacent Regions (CARIBE EWS) was established in 2005 to coordinate and advance the regional tsunami warning system. The CARIBE EWS focuses on four areas/working groups: (1) Monitoring and Warning, (2) Hazard and Risk Assessment, (3) Communication and (4) Education, Preparedness and Readiness. The sea level monitoring component is under Working Group 1. Although in the current system, it's the seismic data and information that generate the initial tsunami bulletins, it is the data from deep ocean buoys (DARTS) and the coastal sea level gauges that are critical for the actual detection and forecasting of tsunamis impact. Despite multiple efforts and investments in the installation of sea level stations in the region, in 2004 there were only a handful of sea level stations operational in the region (Puerto Rico, US Virgin Islands, Bermuda, Bahamas). Over the past 5 years there has been a steady increase in the number of stations operating in the Caribbean region. As of mid 2012 there were 7 DARTS and 37 coastal gauges with additional ones being installed or funded. In order to reach the goal of 100 operational coastal sea level stations in the Caribbean, the CARIBE EWS recognizes also the importance of maintaining the current stations. For this, a trained workforce in the region for the installation, operation and data analysis and quality control is considered to be critical. Since 2008, three training courses have been offered to the sea level station operators and data analysts. Other

  12. Sea Spray Aerosols

    DEFF Research Database (Denmark)

    Butcher, Andrew Charles

    entrainment may account for the large discrepancy in energy input for the two systems. In the third study, the temperature dependence of sea spray aerosol production is probed with the use of a highly stable temperature controlled plunging jet. Similar to previous studies, particle production increases...... of a cloud condensation nuclei ounter. Proxy solutions with high inorganic salt concentrations and some organics produce sea spray aerosol particles with little change in cloud condensation activity relative to pure salts. Comparison is made between a frit based method for bubble production and a plunging...... a relationship between plunging jet particle ux, oceanic particle ux, and energy dissipation rate in both systems. Previous sea spray aerosol studies dissipate an order of magnitude more energy for the same particle ux production as the open ocean. A scaling factor related to the energy expended in air...

  13. Mediterranean, our sea

    Science.gov (United States)

    Markaki, Foteini

    2017-04-01

    My school (1o EPAL Ymittos -Athens, Greece) is a technical school of secondary education and throughout this school year being drafted a program of environmental education. The main theme is the Mediterranean Sea, the biggest closed sea extending between three continents. Topics studied: 1. Biodiversity and the risks threat. 2. The geophysics that characterize (earthquakes, volcanoes explosions, etc). 3. The Mediterranean Sea as environment anthropogenesis, a mosaic of other cultures and even place current notions of social phenomena (refugees). Pedagogical Objectives: Cognitive/Enviromental: 1. To investigate and understand the biodiversity of the Mediterranean Sea and the risks to threaten and phenomena that characterize. 2. To understand the position of the Mediterranean Sea in the land and the role of the historical, cultural and social human environment. 3. To come in contact with texts literary, social, articles on the Mediterranean. Psychomotor: 1. To work together and collect information for the Mediterranean Sea. 2. Experiential approach to the natural environment. 3. Develop critical thinking. 4. Undertake responsibilities for the presentation of the program. Emotional: 1. To feel joy from participation in the program. 2. Being sensitized and configure attitudes and actions of respect towards the environment. Methodology implementation: Teamwork. Interdisciplinary - holistic to dissemination of program recordings to courses curriculum. Study in the field. Gathering information from newspapers, magazines, internet, maps, and photographs. Experiential method- Project. Assessment methods and self-assessment. Fields of courses: Greek language- History- Biology- Chemistry- Technology Dissemination of results: Make a page of social media (facebook), a blog, enhancing environmental awareness via video, make an electronic poster.

  14. Irish Sea: British radioactivity

    International Nuclear Information System (INIS)

    Collins, Aongus

    1985-01-01

    British Nuclear Fuels Ltd. (BNFL) have recently taken the decision to invest several hundred million pounds in reducing the discharges from the Sellafield reprocessing plant into the Irish Sea. This report outlines the history of the plant and its operation up to the present day and its plans for the future. The attitude of the Irish regulatory authorities and of the public to the radioactive discharges is presented and the incidence of Downs Syndrome and certain specific cancer types on both sides of the Irish Sea is discussed

  15. IOMASA SEA ICE DEVELOPMENTS

    DEFF Research Database (Denmark)

    Andersen, Søren; Tonboe, Rasmus; Heygster, Georg

    2005-01-01

    and determine the circumstances that may lead to anomalous sea ice concentration retrieval as well as to assess and possibly minimize the sensitivities of the retrieval system. Through an active partnership with the SAF on Ocean and Sea Ice, a prototype system will be implemented as an experimental product...... chain in order to shorten the loop from development to operational processing. The presentation will present the developments and examples of the new retrievals and finally give an outlook to the future perspectives of the system....

  16. Sea level change

    Digital Repository Service at National Institute of Oceanography (India)

    Church, J.A.; Clark, P.U.; Cazenave, A.; Gregory, J.M.; Jevrejeva, S.; Levermann, A.; Merrifield, M.A.; Milne, G.A.; Nerem, R.S.; Nunn, P.D.; Payne, A.J.; Pfeffer, W.T.; Stammer, D.; Unnikrishnan, A.S.

    .1.1 Introduction and Chapter Overview Changes in sea level occur over a broad range of temporal and spatial scales, with the many contributing factors making it an integral meas- ure of climate change (Milne et al., 2009; Church et al., 2010). The pri- mary... contributors to contemporary sea level change are the expansion of the ocean as it warms and the transfer of water currently stored on land to the ocean, particularly from land ice (glaciers and ice sheets) (Church et al., 2011a). Observations indicate...

  17. Phosphorus dynamics in the Black Sea and Baltic Sea

    NARCIS (Netherlands)

    Dijkstra, N.|info:eu-repo/dai/nl/372617034

    2017-01-01

    The dynamics of the key nutrient phosphorus (P) in hypoxic and anoxic marine basins are still incompletely understood. This thesis focuses on the cycling of P in two of such basins: the Baltic Sea and the Black Sea. Water column particulates and sediments from the deep basin of the Black Sea were

  18. SEA LEVEL (TOPEX/POSEIDON)

    Data.gov (United States)

    National Aeronautics and Space Administration — Sea level rise is caused by the thermal expansion of sea water due to climate warming and widespread melting of land ice. The TOPEX/POSEIDON mission a joint...

  19. P-wave velocity models of continental shelf of East Siberian Sea using the Laplace-domain full waveform inversion

    Science.gov (United States)

    Kang, S. G.; Hong, J. K.; Jin, Y. K.; Jang, U.; Niessen, F.; Baranov, B.

    2017-12-01

    2016 IBRV ARAON Arctic Cruise Leg-2, Expedition ARA07C was a multidisciplinary undertaking carried out in the East Siberian Sea (ESS) from August 25 to September 10, 2016. The program was conducted as a collaboration between the Korea Polar Research Institute (KOPRI), P.P. Shirshov Institute of Oceanology (IORAS), and Alfred Wegener Institute (AWI). During this expedition, the multi-channel seismic (MCS) data were acquired on the continental shelf and the upper slope of the ESS, totaling 3 lines with 660 line-kilometers. The continental shelf of ESS is one of the widest shelf seas in the world and it is believed to cover the largest area of sub-sea permafrost in the Arctic. According to the present knowledge of the glacial history of the western Arctic Ocean, it is likely that during the LGM with a sea level approximately 120 m below present, the entire shelf area of the ESS was exposed to very cold air temperatures so that thick permafrost should have formed. Indeed, in water depths shallower than 80 m, sub-bottom profiles in the ESS recorded from the shelf edge to a latitude of 74°30' N in 60 m water depth exhibited acoustic facies, suggesting that at least relicts of submarine permafrost are present. In order to identify the existence and/or non-existence of subsea permafrost in our study area, we analyze the MCS data using the Laplace domain full waveform inversion (FWI). In case of the Canadian continental shelf of the Beaufort Sea, subsea permafrost has high seismic velocity values (over 2.6 km/sec) and strong refraction events were found in the MCS shotgathers. However, in the EES our proposed P-wave velocity models derived from FWI have neither found high velocity structures (over 2.6 km/sec) nor indicate strong refraction events by subsea permafrost. Instead, in 300 m depth below sea floor higher P-wave velocity structures (1.8 2.2 km/s) than normal subsea sediment layers were found, which are interpreted as cemented strata by glaciation activities.

  20. Pollution of Coastal Seas

    Indian Academy of Sciences (India)

    Pollution of various environments is a consequence of population growth and industrialisation. Coastal seas form part of marine environment and are very rich in minerals, crude oil, fishes etc. They are also being used for disposal of wastes from cities. Various types of wastes, if not properly treated, would cause serious ...

  1. Solomon's Sea and [Pi

    Science.gov (United States)

    Simoson, Andrew J.

    2009-01-01

    This paper is a whimsical survey of the various explanations which might account for the biblical passage in I Kings 7:23 that describes a round object--a bronze basin called Solomon's Sea--as having diameter ten cubits and circumference thirty cubits. Can the biblical pi be any number other than 3? We offer seven different perspectives on this…

  2. Solar Sea Power

    Science.gov (United States)

    Zener, Clarence

    1976-01-01

    In their preoccupation with highly complex new energy systems, scientists and statesmen may be overlooking the possibilities of Ocean Thermal Energy Conversion (OTEC). That is the view of a Carnegie-Mellon University physicist who is in the forefront of solar sea power investigation. (Author/BT)

  3. AFSC/RACE/EcoFOCI - Zooplankton data collected in support of FOCI assessment surveys and ecosystem observations in the Bering, Beaufort, and Chukchi Seas and the Gulf of Alaska, 1987 – Present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton data are abundance by taxanomic group (to species where possible), stage, size and sex. Zooplankton sorting is performed at The Polish Plankton Sorting...

  4. AFSC/RACE/EcoFOCI - Physical oceanographic data collected in support of EcoFOCI assessment surveys and ecosystem observations in the Bering, Beaufort, and Chukchi Seas and the Gulf of Alaska - 1995 to Present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pressure, temperature and salinity data. Data are available in 1 meter intervals in conjunction with the MARMAP 20/60 bongo array, CalVET, and Tucker trawl. Maximum...

  5. CURRENT DIRECTION, turbidity and other data from FIXED STATIONS, DRIFTING PLATFORM and UNKNOWN in the Beaufort Sea from 1985-01-01 to 1988-12-31 (NODC Accession 9400070)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The database from the Endicott Environmental Monitoring Program contains oceanographic, meterological, and fisheries data for the Prudhoe Bay region (North Alaska,...

  6. Underway meteorological, navigational, physical and time series data collected aboard NOAA Ship Ronald H. Brown in the Arctic Ocean, Beaufort Sea and others from 2015-08-06 to 2015-09-04 (NCEI Accession 0141104)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0141104 contains raw underway meteorological, navigational, physical and time series data logged by the Scientific Computer System (SCS) aboard NOAA...

  7. AFSC/RACE/EcoFOCI - Otolith measurements and analyses performed in support of FOCI assessment surveys and ecosystem observations in the Bering, Beaufort, and Chukchi Seas and the Gulf of Alaska. 1995 - Present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Otolith data are collected to measure age and growth of larval pollock. They are used to determine whether growth rate, hatch data and/or temperature influence fish...

  8. Visual surveys of cetaceans conducted in the Bering, Chukchi, and Beaufort Seas by Alaska Fisheries Science Center, National Marine Mammal Laboratory from 2010-08-25 to 2015-09-28 (NCEI Accession 0137906)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of several inter-agency agreements between the National Marine Mammal Laboratory (NMML) and the Bureau of Ocean Energy Management (BOEM), visual surveys of...

  9. Aerial surveys of bowhead and beluga whales along with incidental sighting of other marine mammals in the Bering, Beaufort and Chukchi Seas for the Bowhead Whale Aerial Survey Project (BWASP), 1979 - 2004 (NODC Accession 0001941)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Minerals Management Service (MMS), previously Bureau of Land Management, has funded fall bowhead whale aerial surveys in this area each year since 1978, using a...

  10. Periodic bowhead whale aerial surveys by the USDI/Minerals Management Service in the Bering, Chukchi and Beaufort Seas, 1979-04 to 2001-10 (NODC Accession 0001139)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Minerals Management Service (MMS), previously Bureau of Land Management, has funded fall bowhead whale aerial surveys in this area each year since 1978, using a...

  11. Aerial sightings of bowhead whales and other marine mammals by the US Department of the Interior's Minerals Management Service, 1979 - 2006, in the Bering, Chukchi and Beaufort Seas (NODC Accession 0014906)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Minerals Management Service (MMS), previously Bureau of Land Management, has funded fall bowhead whale aerial surveys in this area each year since 1978, using a...

  12. Physical, chemical, and biological data collected in the Beaufort Sea as part of the Arctic Nearshore Impact Monitoring in the Development Area (ANIMIDA) from 1999 to 2007 (NODC Accession 0001921)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data contains information specifically for the Arctic Nearshore Impact Monitoring in the Development Area (ANIMIDA 1999 - 2002) and continuation of Arctic...

  13. Sea floor magnetic observatory

    Science.gov (United States)

    Korepanov, V.; Prystai, A.; Vallianatos, F.; Makris, J.

    2003-04-01

    The electromagnetic precursors of seismic hazards are widely accepted as strong evidence of the approaching earthquake or volcano eruption. The monitoring of these precursors are of main interest in densely populated areas, what creates serious problems to extract them at the strong industrial noise background. An interesting possibility to improve signal-to-noise ratio gives the installation of the observation points in the shelf zones near the possible earthquake places, what is fairly possible in most seismically active areas in Europe, e. g. in Greece and Italy. The serious restriction for this is the cost of the underwater instrumentation. To realize such experiments it requires the unification of efforts of several countries (e. g., GEOSTAR) or of the funds of some great companies (e. g., SIO magnetotelluric instrument). The progress in electronic components development as well as the appearance of inexpensive watertight glass spheres made it possible to decrease drastically the price of recently developed sea floor magnetic stations. The autonomous vector magnetometer LEMI-301 for sea bed application is described in the report. It is produced on the base of three-component flux-gate sensor. Non-magnetic housing and minimal magnetism of electronic components enable the instrument to be implemented as a monoblock construction where the electronic unit is placed close to the sensor. Automatic circuit provides convenient compensation of the initial field offset and readings of full value (6 digits) of the measured field. Timing by internal clock provides high accuracy synchronization of data. The internal flash memory assures long-term autonomous data storage. The system also has two-axes tilt measurement system. The methodological questions of magnetometer operation at sea bed were studied in order to avoid two types of errors appearing at such experimental cases. First is sea waving influence and second one magnetometer orientation at its random positioning on

  14. The radioactivity of the sea

    International Nuclear Information System (INIS)

    Walker, M.I.; Rose, K.S.B.

    1990-01-01

    The radioactivity in the world's surface sea water averages 13.6 Bq/kg of water. Over 88% of this activity arises from a single natural radionuclide, 40 K, and 7% of the remainder results from nuclear weapon test fallout. Variations in the radioactivity occur due to changes in salinity, weapon test fallout and discharges of artificial radionuclides, and are examined here on the basis of published measurements. The most radioactive sea identified by these measurements is the Dead Sea, which averages 178 Bq/kg due to its high salinity. Other enclosed, highly saline waters can be expected to have similar levels. The radioactivity in open seas varies within a much narrower range, generally within 20% of the world average. The highest averages are found in the Persian Gulf (22 Bq/kg), the Red Sea (15 Bq/kg) and the Eastern Mediterranean (14.6 Bq/kg). The Irish Sea averaged 13.7 Bq/kg in 1987, with the effect of the Sellafield discharges being partly offset by lower than average salinity. Although higher levels occurred in the Irish Sea during the 1970s when the Sellafield discharges were higher, the average level has always been much less than that in the Dead Sea, so that the Irish Sea has never been the most radioactive sea in the world. Exceptionally low levels of radioactivity (4 Bq/kg) occur in the Baltic Sea due to dilution by fresh water. (author)

  15. Black Sea challenges

    International Nuclear Information System (INIS)

    Drevet, J.F.

    2008-01-01

    In this month's European column, Jean-Francois Drevet examines the issues that arise for Europe from the Black Sea region. The Black Sea is increasingly becoming a crucial place of transit for hydrocarbon imports from the Caspian and Russia into the European Union. The considerable increase in this traffic raises both environmental problems (the risk of oil slicks) and issues of security of supply, on account of the economic and political fragility of some of the bordering or neighbouring states (Ukraine, Georgia, Armenia, Azerbaijan, Russia/Chechnya etc.). This is why, as Jean-Francois Drevet stresses, the European Union has been trying since the mid-1990's to claim a role in the management of the affairs of the region. With two bordering states (Rumania and Bulgaria) joining the EU in 2007, cooperation in the Black Sea has become a priority within the framework of the European Neighbourhood Policy, and this column delineates a number of the obstacles that still have to be surmounted. (author)

  16. Effectiveness and Sensitivity of the Arctic Observing Network in a Coupled Ocean-Sea Ice State Estimation Framework

    Science.gov (United States)

    Nguyen, A. T.; Heimbach, P.; Garg, V.; Ocana, V.

    2016-12-01

    Over the last few decades, various agencies have invested heavily in the development and deployment of Arctic ocean and sea ice observing platforms, especially moorings, profilers, gliders, and satellite-based instruments. These observational assets are heterogeneous in terms of variables sampled and spatio-temporal coverage, which calls for a dynamical synthesis framework of the diverse data streams. Here we introduce an adjoint-based Arctic Subpolar gyre sTate estimate (ASTE), a medium resolution model-data synthesis that leverages all the possible observational assets. Through an established formal state and parameter estimation framework, the ASTE framework produces a 2002-present ocean-sea ice state that can be used to address Arctic System science questions. It is dynamically and kinematically consistent with known equations of motion and consistent with observations. Four key aspects of ASTE will be discussed: (1) How well is ASTE constrained by the existing observations; (2) which data most effectively constrain the system, and what impact on the solution does spatial and temporal coverage have; (3) how much information does one set of observation (e.g. Fram Strait heat transport) carry about a remote, but dynamically linked component (e.g. heat content in the Beaufort Gyre); and (4) how can the framework be used to assess the value of hypothetical observations in constraining poorly observed parts of the Arctic Ocean and the implied mechanisms responsible for the changes occurring in the Arctic. We will discuss the suggested geographic distribution of new observations to maximize the impact on improving our understanding of the general circulation, water mass distribution and hydrographic changes in the Arctic.

  17. Quantification of sea ice production in Weddell Sea polynyas

    Science.gov (United States)

    Zentek, Rolf; Heinemann, Günther; Paul, Stephan; Stulic, Lukrecia; Timmermann, Ralph

    2017-04-01

    The regional climate model COSMO-CLM was used to perform simulations the Weddell Sea region in Antarctica for the time period 2002-2015 with the focus on atmosphere-ocean-sea ice interactions. The original model was adapted to polar regions by the use of a thermodynamic sea ice module with snow cover and an temperature-dependent albedo scheme for sea ice. The recently published topography RTopo2 was used. The model was run with nesting in ERA-Interim data in a forecast mode. Sea ice concentrations were taken from satellite measurements (AMSR-E, SSMI/S, AMSR2) and were updated daily to allow for a close-to-reality hindcast. Simulations were done with 15 km resolution for the whole period 2002-2015 with the goal to force the sea-ice ocean model FESOM. In a second step a 5 km simulation was one-way nested for the winter period (April - September) 2002-2015 to allow for a better quantification of sea ice production in the Weddell Sea. Estimates of sea ice production and comparisons of the results to remote sensing data will be presented.

  18. Highly variable Pliocene sea surface conditions in the Norwegian Sea

    Science.gov (United States)

    Bachem, Paul E.; Risebrobakken, Bjørg; De Schepper, Stijn; McClymont, Erin L.

    2017-09-01

    The Pliocene was a time of global warmth with small sporadic glaciations, which transitioned towards the larger-scale Pleistocene glacial-interglacial variability. Here, we present high-resolution records of sea surface temperature (SST) and ice-rafted debris (IRD) in the Norwegian Sea from 5.32 to 3.14 Ma, providing evidence that the Pliocene surface conditions of the Norwegian Sea underwent a series of transitions in response to orbital forcing and gateway changes. Average SSTs are 2 °C above the regional Holocene mean, with notable variability on millennial to orbital timescales. Both gradual changes and threshold effects are proposed for the progression of regional climate towards the Late Pliocene intensification of Northern Hemisphere glaciation. Cooling from 4.5 to 4.3 Ma may be linked to the onset of poleward flow through the Bering Strait. This cooling was further intensified by a period of cool summers due to weak obliquity forcing. A 7 °C warming of the Norwegian Sea at 4.0 Ma suggests a major increase in northward heat transport from the North Atlantic, leading to an enhanced zonal SST gradient in the Nordic Seas, which may be linked to the expansion of sea ice in the Arctic and Nordic Seas. A warm Norwegian Sea and enhanced zonal temperature gradient between 4.0 and 3.6 Ma may have been a priming factor for increased glaciation around the Nordic Seas due to enhanced evaporation and precipitation at high northern latitudes.

  19. Observational analysis of air-sea fluxes and sea water temperature offshore South China Sea

    Science.gov (United States)

    Bi, X.; Huang, J.; Gao, Z.; Liu, Y.

    2017-12-01

    This paper investigates the air-sea fluxes (momentum flux, sensible heat flux and latent heat flux) from eddy covariance method based on data collected at an offshore observation tower in the South China Sea from January 2009 to December 2016 and sea water temperature (SWT) on six different levels based on data collected from November 2011 to June 2013. The depth of water at the tower over the sea averages about 15 m. This study presents the in-situ measurements of continuous air-sea fluxes and SWT at different depths. Seasonal and diurnal variations in air-sea fluxes and SWT on different depths are examined. Results show that air-sea fluxes and all SWT changed seasonally; sea-land breeze circulation appears all the year round. Unlike winters where SWT on different depths are fairly consistent, the difference between sea surface temperature (SST) and sea temperature at 10 m water depth fluctuates dramatically and the maximum value reaches 7 °C during summer.

  20. Sea Otter, River Otter. The Wonder Series.

    Science.gov (United States)

    Robinson, Sandra Chisholm

    This curriculum guide is all about otters and provides information on both sea and river otters. Included are activities related to the diet of sea otters, the adaptations sea otters have made to live in the sea, their tool-using abilities, where they live and how to spot them, comparative anatomy of sea and river otters, and otter movement. The…

  1. Japan nuclear ship sea trial

    International Nuclear Information System (INIS)

    Yamazaki, Hiroshi; Kitamura, Toshikatus; Mizushima, Toshihiko

    1992-01-01

    The sea trial of the first Japan nuclear Ship 'MUTSU' was conducted from the end of October to December in 1990. The purpose of the sea trial was to verify the nuclear propulsive performances and maneuverabilities. The present report describes the results of the sea trial. These results are classified into four items: 1. Speed test and engineering performance tests 2. Maneuvering performance tests 3. Vibration tests 4. Other tests. Acceptable performances were demonstrated, as expected in the original design. The experience of the use of the Global Positioning System (GPS), which were newly adopted for the sea trial, is also reported. (author)

  2. Sea Urchin Morphogenesis.

    Science.gov (United States)

    McClay, David R

    2016-01-01

    In the sea urchin morphogenesis follows extensive molecular specification. The specification controls the many morphogenetic events and these, in turn, precede patterning steps that establish the larval body plan. To understand how the embryo is built it was necessary to understand those series of molecular steps. Here an example of the historical sequence of those discoveries is presented as it unfolded over the last 50 years, the years during which major progress in understanding development of many animals and plants was documented by CTDB. In sea urchin development a rich series of experimental studies first established many of the phenomenological components of skeletal morphogenesis and patterning without knowledge of the molecular components. The many discoveries of transcription factors, signals, and structural proteins that contribute to the shape of the endoskeleton of the sea urchin larva then followed as molecular tools became available. A number of transcription factors and signals were discovered that were necessary for specification, morphogenesis, and patterning. Perturbation of the transcription factors and signals provided the means for assembling models of the gene regulatory networks used for specification and controlled the subsequent morphogenetic events. The earlier experimental information informed perturbation experiments that asked how patterning worked. As a consequence it was learned that ectoderm provides a series of patterning signals to the skeletogenic cells and as a consequence the skeletogenic cells secrete a highly patterned skeleton based on their ability to genotypically decode the localized reception of several signals. We still do not understand the complexity of the signals received by the skeletogenic cells, nor do we understand in detail how the genotypic information shapes the secreted skeletal biomineral, but the current knowledge at least outlines the sequence of events and provides a useful template for future

  3. Alaska Phocid Argos Telemetry Archive (2004-2013)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Polar Ecosystems Program conducts research and monitoring on phocid seals in the East Bering Sea, West Bering Sea, Gulf of Alaska, Beaufort Sea, and Chukchi Sea...

  4. Intraseasonal sea surface temperature variability in Indonesian seas

    Science.gov (United States)

    Napitu, A. M.; Gordon, A. L.; Yuan, X.

    2012-12-01

    The satellite-derived sea surface temperature (SST) data, 1998-mid 2012, are used to examine intraseasonal variability (ISV; 20-90 days) across the Indonesian seas. The most energetic ISV is observed in the Banda Sea and across the Indo-Australia basin with an The satellite-derived sea surface temperature (SST) data, 1998-mid 2012, are used to examine intraseasonal variability (ISV; 20-90 days) across the Indonesian seas. The most energetic ISV is observed in the Banda Sea and across the Indo-Australia basin with an average SST standard deviation (STD) between 0.4-0.5°C, with strongest signature during boreal winter. What physical processes force the SST ISV variability within the Indonesian seas? Ocean process, sea-air interaction, or both? To help identify the main forcing, the satellite derived outgoing longwave radiation (OLR) and wind stress data in the region are examined. The OLR shows robust intraseasonal variations and is significantly correlated with the SST, particularly for variability with periods of 30-60 days, with OLR accounting for ~60-70% of the SST variance. The OLR is also maximum during boreal winter. Conversely, the surface wind may play insignificant role in perturbing the SST at intraseasonal timescales as shown by weak correlation between wind stress and SST. We thus suspect that the surface solar flux (suggested by the OLR) is likely more dominant than the surface turbulent heat flux (indicated by the surface wind) as the main source for the ISV in the SST in Indonesian seas. Furthermore the maximum OLR phase, coupled with a period of minimum mixed layer depth, may explain the strong SST variation during boreal winter in Indonesian seas. The influence of the Madden-Julian Oscillation (MJO) on the OLR and SST variability is currently being evaluated.

  5. EASE-Grid Sea Ice Age

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides weekly estimates of sea ice age for the Arctic Ocean from remotely sensed sea ice motion and sea ice extent. The ice age data are derived from...

  6. Changes in the Seasonal Cycle of δ18Op at Barrow, AK, US Between 1962 and 2013 Reflect the Importance of Proximal Sea Ice Coverage for Coastal Arctic Hydrology

    Science.gov (United States)

    Putman, A.; Feng, X.; Posmentier, E. S.; Bowen, G. J.

    2017-12-01

    The Arctic is sensitive to climate change, exhibiting increases in sea surface temperatures, coupled with decreased sea ice cover. The potential for increased local evaporative flux may affect the Arctic hydrologic cycle in two ways. The first is the direct effect of increased local vapor supply, which is supported by studies using isotope-enabled atmospheric circulation models. The second is an indirect effect via warming of Arctic associated with decreased sea ice cover. Changes in temperature gradient between the mid-latitudes and Arctic may affect circulation and thus meridional vapor flux. The isotopic observations combined with moisture source conditions may help disentangle the direct and indirect effects of sea ice change on Arctic hydrology and climate. We use two precipitation δ18O datasets, from 1962-1969 and 2009-2013, to investigate the hydrological response to sea ice cover changes on the seasonal scale at Barrow, AK, US, where strong seasonal variability and multi-decadal decrease in local summer/fall sea ice coverage are well documented. Previous research has shown that the vapor supplying June through November precipitation at Barrow originates in the Beaufort and Chukchi seas, while December through May precipitation is supplied by vapor evaporated in the North Pacific and Gulf of Alaska. The seasonal cycle of δ18Op is amplified in the more recent dataset (-9.1‰ to -26.3‰) relative to the historic one (-12.9‰ to -24.9‰), with lower δ18Op during December through May and higher δ18Op during June through November. Deuterium excess tends to be greater during all months except July through September. The decrease in δ18Op during the cold season may indicate a change to water vapor transport to Barrow. May and November exhibited the greatest changes in δ18Op and d-excess. The May decrease in δ18Op of 8.3‰ and deuterium excess increase of 21‰ coupled with MODIS imagery from May 2011 that shows open ocean near Barrow, suggests that

  7. Towards Good Order at Sea

    DEFF Research Database (Denmark)

    Mandrup, Thomas; Vreÿ, Francois

    structural problems facing attempts to create and maintain good order at sea off East Africa. As mentioned in one of the chapters, the most secure place for a criminal in East Africa to be is at sea, because most African littoral states have only limited capacity to police their territorial waters...

  8. Governance of the Wadden Sea

    NARCIS (Netherlands)

    Slob, Adriaan F.L.; Geerdink, T.R.A.; Rockmann, Christine; Vöge, S.

    2016-01-01

    The Wadden Sea is a unique area from ecological, geological and cultural perspectives and lies in the territories of Denmark, Germany and the Netherlands. The trilateral cooperation on the protection of the Wadden Sea can be marked to start in 1978, although the countries already cooperated

  9. Sea Level Rise Data Discovery

    Science.gov (United States)

    Quach, N.; Huang, T.; Boening, C.; Gill, K. M.

    2016-12-01

    Research related to sea level rise crosses multiple disciplines from sea ice to land hydrology. The NASA Sea Level Change Portal (SLCP) is a one-stop source for current sea level change information and data, including interactive tools for accessing and viewing regional data, a virtual dashboard of sea level indicators, and ongoing updates through a suite of editorial products that include content articles, graphics, videos, and animations. The architecture behind the SLCP makes it possible to integrate web content and data relevant to sea level change that are archived across various data centers as well as new data generated by sea level change principal investigators. The Extensible Data Gateway Environment (EDGE) is incorporated into the SLCP architecture to provide a unified platform for web content and science data discovery. EDGE is a data integration platform designed to facilitate high-performance geospatial data discovery and access with the ability to support multi-metadata standard specifications. EDGE has the capability to retrieve data from one or more sources and package the resulting sets into a single response to the requestor. With this unified endpoint, the Data Analysis Tool that is available on the SLCP can retrieve dataset and granule level metadata as well as perform geospatial search on the data. This talk focuses on the architecture that makes it possible to seamlessly integrate and enable discovery of disparate data relevant to sea level rise.

  10. ~.",It SEA ~ ~~~

    Indian Academy of Sciences (India)

    The Effect of Tropospheric Weather Conditions on VHF and UHF Radio Paths Over the Sea. 5 D Gunashekar, D R Siddle and E M Warrington. Flowering Trees. (Credits: KSankara Rao,IISc, and K Sridharan, Banga- lore) .... RADIO SIGNAL WITH ONE SEA SURFACE. REFLECTION AND TWO TOP-OF-DUCT ...

  11. The Law of the Sea

    Science.gov (United States)

    Levy, Jean-Pierre

    1978-01-01

    Recounts problems related to the law of the sea and suggests that these problems could be dealt with in the classroom in an interdisciplinary manner. Problems include pollution control, fishing rights, development of deep sea mineral deposits, and shore access. (Author/DB)

  12. The Barbados Sea Level Record

    Science.gov (United States)

    Fairbanks, R. G.; Mortlock, R. A.; Abdul, N. A.; Wright, J. D.; Cao, L.; Mey, J. L.

    2013-12-01

    Additional offshore drill cores, nearly 100 new radiometric dates, and more than 1000 kilometers of Multibeam mapping greatly enhance the Barbados Sea Level record. Extensive Multibeam mapping around the entire island covers approximately 2650 km2 of the sea bottom and now integrates the offshore reef topography and Barbados Sea Level Record with the unparalleled onshore core collection, digital elevation maps, and Pleistocene sea level record spanning the past one million years. The reef crest coral, Acropora palmata, remains the stalwart indicator of sea level for many reasons that are validated by our redundant sea level records and redundant dating via Th/U and Pa/U analyses. Microanalysis and densitometry studies better explain why Acropora palmata is so well preserved in the Pleistocene reef records and therefore why it is the species of choice for sea level reconstructions and radiometric dating. New drill cores into reefs that formed during Marine Isotope Stage 3 lead us to a model of diagenesis that allows us to better prospect for unaltered coral samples in older reefs that may be suitable for Th/U dating. Equally important, our diagenesis model reinforces our rigorous sample quality criteria in a more quantitative manner. The Barbados Sea Level record has a sampling resolution of better than 100 years throughout much of the last deglaciation showing unprecedented detail in redundant drill cores. The Melt Water Pulses (MWP1A and MWP1B) are well resolved and the intervening interval that includes the Younger Dryas reveals sea level changes in new detail that are consistent with the terrestrial records of ice margins (see Abdul et al., this section). More than 100 paired Th/U and radiocarbon ages place the Barbados Sea Level Record unambiguously on the radiocarbon time scale for direct comparisons with the terrestrial records of ice margin changes.

  13. The Wadden Sea in transition - consequences of sea level rise

    Science.gov (United States)

    Becherer, Johannes; Hofstede, Jacobus; Gräwe, Ulf; Purkiani, Kaveh; Schulz, Elisabeth; Burchard, Hans

    2018-01-01

    The impact of sea level rise (SLR) on the future morphological development of the Wadden Sea (North Sea) is investigated by means of extensive process-resolving numerical simulations. A new sediment and morphodynamic module was implemented in the well-established 3D circulation model GETM. A number of different validations are presented, ranging from an idealized 1D channel over a semi-idealized 2D Wadden Sea basin to a fully coupled realistic 40-year hindcast without morphological amplification of the Sylt-Rømøbight, a semi-enclosed subsystem of the Wadden Sea. Based on the results of the hindcast, four distinct future scenarios covering the period 2010-2100 are simulated. While these scenarios differ in the strength of SLR and wind forcing, they also account for an expected increase of tidal range over the coming century. The results of the future projections indicate a transition from a tidal-flat-dominated system toward a lagoon-like system, in which large fractions of the Sylt-Rømøbight will remain permanently covered by water. This has potentially dramatic implications for the unique ecosystem of the Wadden Sea. Although the simulations also predict an increased accumulation of sediment in the back-barrier basin, this accumulation is far too weak to compensate for the rise in mean sea level.

  14. Highly variable Pliocene sea surface conditions in the Norwegian Sea

    Directory of Open Access Journals (Sweden)

    P. E. Bachem

    2017-09-01

    Full Text Available The Pliocene was a time of global warmth with small sporadic glaciations, which transitioned towards the larger-scale Pleistocene glacial–interglacial variability. Here, we present high-resolution records of sea surface temperature (SST and ice-rafted debris (IRD in the Norwegian Sea from 5.32 to 3.14 Ma, providing evidence that the Pliocene surface conditions of the Norwegian Sea underwent a series of transitions in response to orbital forcing and gateway changes. Average SSTs are 2 °C above the regional Holocene mean, with notable variability on millennial to orbital timescales. Both gradual changes and threshold effects are proposed for the progression of regional climate towards the Late Pliocene intensification of Northern Hemisphere glaciation. Cooling from 4.5 to 4.3 Ma may be linked to the onset of poleward flow through the Bering Strait. This cooling was further intensified by a period of cool summers due to weak obliquity forcing. A 7 °C warming of the Norwegian Sea at 4.0 Ma suggests a major increase in northward heat transport from the North Atlantic, leading to an enhanced zonal SST gradient in the Nordic Seas, which may be linked to the expansion of sea ice in the Arctic and Nordic Seas. A warm Norwegian Sea and enhanced zonal temperature gradient between 4.0 and 3.6 Ma may have been a priming factor for increased glaciation around the Nordic Seas due to enhanced evaporation and precipitation at high northern latitudes.

  15. Uranium from sea water

    International Nuclear Information System (INIS)

    Westermark, T.; Forsberg, S.

    1980-01-01

    The prevalent situation in the field of uranium extraction from the oceans was reviewed from a scientific and technological standpoint and as to legality too. No international convention seems to limit the access to dissolved or suspended matter in free area of the oceans. All publications received through 1979 point to adsorption as the method of choice, at some form of hydrated titanium ''oxide'' as the most promising sorbent, and, generally spoken, at the cost of pumping water through the contacting system as a huge economical problem. A recent Swedish invention may circumvent the pumping problem by making available, in a previously unknown manner, some kind of self-renewing energy from the oceans. A simple economic calculus has resulted in costs from two to six times the present world market price of crude uranium oxide (which is assumed to be US dollar 43.-/1b), with a possibility to compete really after some technical and systematic developments. Results from a small-scale adsorption experiment in genuine sea water are presented: During a few weeks sea water was pumped through tiny, 10 cm high beds of sodium titanate ion exchangers, partly in the hydrogen form. The grain size was 250-500 μm, the flow rate 0.15-0.61 m/min. About 5% of the total amount of uranium passing the columns was retained, resulting in 8-11 μg/Ug. Also, large amounts of manganese, strontium, vanadium and zink were retained. Some of these elements and plankton as well may perhaps be recovered with an economic gain

  16. Fire in the Sea

    Science.gov (United States)

    Friedrich, Walter L.

    2000-05-01

    The legend of the lost city of Atlantis has captivated the human imagination for centuries. Did this city actually exist, and, if so, what happened to it? Was it destroyed in the greatest cataclysmic event of the Bronze Age? While the truth behind the legend of Atlantis may never be known, Fire in the Sea tells the story of one of the largest and most devastating natural disasters of classical history that may also hold vital clues to the possible existence and fate of the lost city. In vivid prose, author Walter L. Friedrich describes the eruption of the Greek island of Santorini, or Thera, sometime in the 17th or 16th century BC. This eruption, perhaps one of the largest explosions ever witnessed by humankind, sent a giant cloud of volcanic ash into the air that eventually covered settlements on the island. Friedrich relates how this event forever altered the course of civilization in the region, and inspired a mystery that has fired humanity's imagination ever since. More than 160 elegant, full-color photographs and vivid prose capture the beauty, the geology, archaeology, history, peoples and environmental setting of Santorini. Fire in the Sea will readily appeal to the general reader interested in natural catastrophies as well as the beauty of the region. It will also enchant anyone who has ever dreamt about uncovering the mystery of the legend of Atlantis. Walter Friedrich is currently an associate professor at the Department of Earth Sciences, University of Aarhus, Denmark. He has visited Santorini at least 35 times since 1975 and has published numerous scientific articles in such international journals as Nature, Lethaia, Spektrum der Wissenschaft, and other publications.

  17. Bindin from a sea star.

    Science.gov (United States)

    Patiño, Susana; Aagaard, Jan E; MacCoss, Michael J; Swanson, Willie J; Hart, Michael W

    2009-01-01

    The genetic basis for the evolution of development includes genes that encode proteins expressed on the surfaces of sperm and eggs. Previous studies of the sperm acrosomal protein bindin have helped to characterize the adaptive evolution of gamete compatibility and speciation in sea urchins. The absence of evidence for bindin expression in taxa other than the Echinoidea has limited such studies to sea urchins, and led to the suggestion that bindin might be a sea urchin-specific molecule. Here we characterize the gene that encodes bindin in a broadcast-spawning asterinid sea star (Patiria miniata). We describe the sequence and domain structure of a full-length bindin cDNA and its single intron. In comparison with sea urchins, P. miniata bindin is larger but the two molecules share several general features of their domain structure and some sequence features of two domains. Our results extend the known evolutionary history of bindin from the Mesozoic (among the crown group sea urchins) into the early Paleozoic (and the common ancestor of eleutherozoans), and present new opportunities for understanding the role of bindin molecular evolution in sexual selection, life history evolution, and speciation among sea stars.

  18. Deep-sea geohazards in the South China Sea

    Science.gov (United States)

    Wu, Shiguo; Wang, Dawei; Völker, David

    2018-02-01

    Various geological processes and features that might inflict hazards identified in the South China Sea by using new technologies and methods. These features include submarine landslides, pockmark fields, shallow free gas, gas hydrates, mud diapirs and earthquake tsunami, which are widely distributed in the continental slope and reefal islands of the South China Sea. Although the study and assessment of geohazards in the South China Sea came into operation only recently, advances in various aspects are evolving at full speed to comply with National Marine Strategy and `the Belt and Road' Policy. The characteristics of geohazards in deep-water seafloor of the South China Sea are summarized based on new scientific advances. This progress is aimed to aid ongoing deep-water drilling activities and decrease geological risks in ocean development.

  19. How SEA can inform lenders

    DEFF Research Database (Denmark)

    Banhalmi-Zakar, Zsuzsa; Larsen, Sanne Vammen

    SEA can be a powerful tool to improve decision-making for plans, policies and programmes, but it can also be a useful for banks. SEA can help lenders address the reputational risks they are exposed to through financing projects that may have a negative impact on the environment and it can also help......, such as in the credit policies. It was also found that in some cases lenders become involved in project planning at a very early stage, when projects are conceptualized, and certainly before formal approval is sought from relevant authorities and an EIA is conducted. This suggests that SEA can be a useful tool...

  20. 33 CFR 2.32 - High seas.

    Science.gov (United States)

    2010-07-01

    ... the High Seas in Cases of Oil Pollution Casualties, 1969, including annexes thereto), high seas means... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false High seas. 2.32 Section 2.32... Jurisdictional Terms § 2.32 High seas. (a) For purposes of special maritime and territorial jurisdiction of the...

  1. Primary production in the Sulu Sea

    Indian Academy of Sciences (India)

    The greater primary productivity may provide the explanation for the higher deposition rate of carbon in the Sulu Sea. Although the Sulu Sea is more productive than the adjacent South China Sea, the central area can still be classified as a desert. Estimates of the new primary production in the central Sulu Sea seem to be ...

  2. Doppler characteristics of sea clutter.

    Energy Technology Data Exchange (ETDEWEB)

    Raynal, Ann Marie; Doerry, Armin Walter

    2010-06-01

    Doppler radars can distinguish targets from clutter if the target's velocity along the radar line of sight is beyond that of the clutter. Some targets of interest may have a Doppler shift similar to that of clutter. The nature of sea clutter is different in the clutter and exo-clutter regions. This behavior requires special consideration regarding where a radar can expect to find sea-clutter returns in Doppler space and what detection algorithms are most appropriate to help mitigate false alarms and increase probability of detection of a target. This paper studies the existing state-of-the-art in the understanding of Doppler characteristics of sea clutter and scattering from the ocean to better understand the design and performance choices of a radar in differentiating targets from clutter under prevailing sea conditions.

  3. Sea Turtle Acoustic Telemetry Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Acoustic transmitters attached to sea turtles captured in various fishing gear enable the animals to be passively tracked. Acoustic receivers set up in an array...

  4. Temperature measurement in the sea

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnamacharyulu, R.J.; Rao, L.V.G.

    ), their advantages and limitations are also touched upon. Calibration of various instruments used for temperature measurement in the sea and the special setup/facilities needed for this purpose are also discussed...

  5. Biological interactions in the Sea

    Indian Academy of Sciences (India)

    ddattesh

    Primary Producers in the sea. Phytoplankton. Light. Temperature. Micro-nutrients. Trace metals. (Iron, Manganese, Zinc, Cobalt, Copper, Molybdenum, Nickel,. Cadmium, Selenium). Vitamins. (Thiamine, Biotin, Vitamin B12). Macro-nutrients. (Nitrogen, Phosphorous, Silicon) ...

  6. Towards Good Order at Sea

    DEFF Research Database (Denmark)

    Mandrup, Thomas; Vreÿ, Francois

    . The problems originating from the resultant “bad order at sea” can be directly felt on land, when smuggling, terrorism and related criminal activities operate more or less unhindered. The book provides an important mapping of the challenges preventing good order at sea off the African coast and East Africa......This book addresses a timely and important theme in the debate on how to create good governance at sea in general, but specifically in the Western Indian Ocean. In a security milieu where the number of piracy attacks originating from Somalia has decreased, there is an urgent need to address...... structural problems facing attempts to create and maintain good order at sea off East Africa. As mentioned in one of the chapters, the most secure place for a criminal in East Africa to be is at sea, because most African littoral states have only limited capacity to police their territorial waters...

  7. Sea Turtle Stranding Network Reports

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Sea Turtle Stranding and Salvage Network (STSSN) was formally established in 1980 to collect information on and document the stranding of marine turtles along...

  8. ISLSCP II Sea Surface Temperature

    Data.gov (United States)

    National Aeronautics and Space Administration — Sea surface temperature (SST) is an important indicator of the state of the earth climate system as well as a key variable in the coupling between the atmosphere and...

  9. Sea bed mapping and inspection

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    The conference has 24 presentations on the topics: Sea bed mapping, inspection, positioning, hydrography, marine archaeology, remote operation vehicles and computerized simulation technologies, oil field activities and plans, technological experiences and problems. (tk)

  10. Black Sea Bass genetic connectivity

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Microsatellite analysis of black sea bass was undertaken to determine magnitude and direction of mixing of black seabass across the Hatteras boundary, as well as...

  11. Denitrification in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.; Noronha, R.J.; Reddy, C.V.G.

    Estimates of the amount of denitrification in the Arabian Sea are inconsistent, and so two methods of calculations of 'original' nitrate concentrations used in earlier studies have been reviewed. Nitrite at intermediate depths was not restricted...

  12. Sea Turtle Satellite Telemetry Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sea turtles captured in various fishing gear (pound nets, long haul seines, gill nets) were outfitted with satellite transmitters so that their movements, migratory...

  13. Alien seas oceans in space

    CERN Document Server

    Lopes, Rosaly

    2013-01-01

    In the early days of planetary observation, oceans were thought to exist in all corners of the Solar System. Carbonated seas percolated beneath the clouds of Venus. Features on the Moon's surface were given names such as "the Bay of Rainbows” and the "Ocean of Storms." With the advent of modern telescopes and spacecraft exploration these ancient concepts of planetary seas have been replaced by the reality of something even more exotic. Alien Seas serves up the current research, past beliefs, and new theories to offer a rich array of the "seas" on other worlds. It is organized by location and by the material composing the oceans under discussion, with expert authors penning chapters on their  specialty. Each chapter features new original art depicting alien seas, as well as the latest ground-based and spacecraft images. With the contributors as guides, readers can explore the wild seas of Jupiter's watery satellite Europa, believed similar in composition to battery acid. Saturn's planet-sized moon Titan see...

  14. Intermittent sea-level acceleration

    Science.gov (United States)

    Olivieri, M.; Spada, G.

    2013-10-01

    Using instrumental observations from the Permanent Service for Mean Sea Level (PSMSL), we provide a new assessment of the global sea-level acceleration for the last ~ 2 centuries (1820-2010). Our results, obtained by a stack of tide gauge time series, confirm the existence of a global sea-level acceleration (GSLA) and, coherently with independent assessments so far, they point to a value close to 0.01 mm/yr2. However, differently from previous studies, we discuss how change points or abrupt inflections in individual sea-level time series have contributed to the GSLA. Our analysis, based on methods borrowed from econometrics, suggests the existence of two distinct driving mechanisms for the GSLA, both involving a minority of tide gauges globally. The first effectively implies a gradual increase in the rate of sea-level rise at individual tide gauges, while the second is manifest through a sequence of catastrophic variations of the sea-level trend. These occurred intermittently since the end of the 19th century and became more frequent during the last four decades.

  15. Bering Strait as a Cenozoic check valve with changes in sea level: What we know about the stability of the -52 m sill

    Science.gov (United States)

    Brigham-Grette, J.

    2016-12-01

    The Cenozoic history of the Bering Strait (BS) region includes GIA, dynamic topography and regional tectonics. Assuming outright, that the BS has been at minus 52 m for the last few million years seems rather simplified. Raymo and Mitrovica (2011) looked at stage 11 terrace elevations and concluded eustatic sea level rose 6-13m asl. Yet the Prism group argues that the BS had to have been closed to ocean circulation 3.2 Ma to explain extreme pan-Arctic warmth. Extralimital boreal mollusks found in Pliocene sites on Ellesmere Island today are limited to coastal Norway. During the PIiocene, if the Arctic was warm, there was no summer sea ice, and probably no Greenland ice sheet — why was BS closed? If it was closed, this poses implications for records from places like Lake El'gygytgyn record too due to implied changes in continentally, etc. Marine terraces from Nome to Barrow, Alaska, record the stratigraphic evidence for high sea level events around 3.2 Ma and perhaps associated with MIS 103, MIS31, MIS 11, MIS 5e and MIS 5a, most of these associated with super interglacials at Lake El'gygytgyn. The Bering Strait was first submerged about 5.5 Ma (Gladenkov et al 2004). This coincides with the rotation of the Bering Sea plate nudged by the northward movement of the N. Pacific plate. BS was open during MIS 5a — allowing whales to migrate to the Beaufort Sea for calving based on bone findings in the Flaxman Formation. The oldest Pliocene shorelines (Colvillan and Bigbendian) are warped in the BS so that the highest elevation with an age of 2.6 Ma is now = to the top of the Diomede Islands at 350 to 363 m asl in BS (a marine wave cut platform) — that shoreline projects eastward into the Alaskan side of BS and dives below modern SL in the area of Teller, Alaska. Thus Pliocene shorelines are warped with the BS raising upward over time. And the 5 e shoreline goes below SL inland of the Alaska mainland. The Clarence Rift trending E-W south of BS has a lot of throw on

  16. Sea-ice production in the northern Japan Sea

    Science.gov (United States)

    Nihashi, Sohey; Ohshima, Kay I.; Saitoh, Sei-Ichi

    2017-09-01

    Sinking of the dense water plays a significant role in the global climate system by driving thermohaline (overturning) circulation and biogeochemical cycles. Deep water convection occurs also in the Japan Sea, and the convection has been considered to be mainly caused by intense cooling of the sea surface. Another possible cause of the convection is brine rejection associated with high sea-ice production in a coastal polynya (thin sea-ice) area in the northern Japan Sea. We have developed an algorithm which detects the thin ice area and estimates the thickness using passive microwave satellite data. Based on a heat flux calculation with the satellite-derived ice thickness, the total sea-ice production in winter (December-March) averaged over 2002/03-2010/11 is estimated to be 4.27 × 1010 m3. This indicates that the ice production was underestimated by about half in a previous study in which the polynya was unrealistically treated as a low ice concentration area. The main determinant factor for the total ice production is the surface air temperature in early winter (December-January), which shows a rapid warming trend of 0.7 °C/decade for this 40-years. Based on a linear regression approach, the total ice production is estimated to have decreased by 5%/decade due to air temperature warming. If brine rejection due to the ice production contributes to the deep water formation in the Japan Sea, this is consistent with the fact that the deep water formation has been decreasing for the last 50-100 years.

  17. Past and present Aral Sea

    Science.gov (United States)

    Dukhovniy, Viktor; Stulina, Galina; Eshchanov, Odylbek

    2013-04-01

    The tragedy of disappearing of Aral Sea is well known to the World. Before and after collapse of Soviet Union, a huge quantity of scientific and popular editions described with grief the situation around the Aral Sea. After the NIS states became independent, World Bank, UNDP, UNEP in proper competition with each other had provided some assessment of the situation through presentation of some small and medium grants, but after 2000, the local population remained alone with own problems. Although on the eyes of the present generation a unique transformation of great water body into deserts took place, the global scientific community did not find forces and financing for real and detail investigation of the processes accompanying the Sea shrinking and land formation. We should acknowledge and give big respect to NATO, later to German Government that through GTZ (now GIZ) - German International Collaboration Agency - and GFZ (Potzdam) paid attention to this area of environment crisis and organized scientific and protective design in the so-called Priaralie - the territory around the drying Sea and delta of the two rivers - Amudarya and Syrdarya. Thank to this assistance, the local specialists in collaboration with limited a number of foreign scientists (N.Aladin, P.Zavialov, Joop de Schutter, Hans Wilps, Hedi Oberhansli) organized significant works for detail socioeconomic, ecological and hydrological assessment situation in Priaralie and on the Aral sea coast. On this base, Ministry of Agriculture and Water resources of Uzbekistan and State Committee of Water resources of Kazakhstan developed a plan of rehabilitation of Amudarya and Syrdarya deltas and started implementation of these projects. If Kazakh water authority moved ahead in wetland restoration faster, a forestation of delta and drying bed of Aral Sea got big success in Uzbek territory. 244 thousands hectares of saxsaul and tamarix were planted for protection of the Priaralie. By request of GTZ SIC, ICWC

  18. Sea level pressure climatology in black sea region

    Directory of Open Access Journals (Sweden)

    Sayed Mohammad Hosseini

    2014-02-01

    Full Text Available In the present study, to achieve a comprehensive view of pressure conditions in the Black Sea region, sea level pressure data in Reanalysis II database in National Centers for Environmental Prediction (NCEP/National Center for Atmospheric Research (NCAR were used. The data temporal resolution is daily and the spatial resolution is 2.5×2.5 degrees of arc. The investigated framework covers the areas between -30-70 degrees east longitude and 20-70 degrees north latitude and has dimensions equal 41×21 pixels consisting of 861 pixels. The studied period of time is 33-year (1979 to 2012 and includes 12419 days and 861 spatial pixels. Therefore, sea level pressure data matrix is 12419×861, which has 12419 temporal pixels and 861 spatial ones. In other words, the arrangement of the data is S-shaped. The rows of the matrix represent time while columns represent space. At the end, using the cluster analysis, six sea level pressure circulation patterns based on the spatial - temporal features were obtained: Red Sea trough is fall pattern; Iraq trough is spring pattern; Persian Gulf trough is transitional pattern; Persian Gulf deep trough is summer pattern; Caucasian high pressure is fall - winter pattern and the Caucasian Strong high pressure is winter pattern. In most of these patterns, intensive allobaric conditions can be observed in the troughs and ridges.

  19. Macroplastics at sea around Antarctica.

    Science.gov (United States)

    Barnes, David K A; Walters, Adam; Gonçalves, Leandra

    2010-08-01

    More so than at any previous time, there is a heightened awareness of the amount of plastic in the environment, it's spread to even remote localities and the multiple influences of this on organisms. In the austral summer of 2007/08 Greenpeace and British Antarctic Survey ships (MV Esperanza and RRS James Clark Ross respectively) conducted the first co-ordinated joint marine debris survey of the planet's most remote seas around East and West Antarctica to reveal floating macroplastics. With observations also made from the ice patrol vessel HMS Endurance in the same season and seabed samples collected from the RRS James Clark Ross, this was the widest survey for plastics ever undertaken around Antarctica. The 2008 visit of RRS James Clark Ross to the Amundsen Sea breached two last frontiers; the last and most remote sea from which biological samples and plastic debris have been reported. A plastic cup and two fishing buoys were seen in the Durmont D'Urville and Davis seas while two pieces of plastic packaging and a fishing buoy were observed in the Amundsen Sea. Agassiz trawls revealed rich biodiversity on the Amundsen (and south Bellingshausen) seabed but no sunken plastic pieces. We found no microplastics in five epibenthic sledge samples (300 microm mesh) from the Amundsen seabed. The seabeds immediately surrounding continental Antarctica are probably the last environments on the planet yet to be reached by plastics, but with pieces floating into the surface of the Amundsen Sea this seems likely to change soon. Our knowledge now touches every sea but so does our legacy of lost and discarded plastic.

  20. Dead sea asphalts: historical aspects

    Energy Technology Data Exchange (ETDEWEB)

    Nissenbaum, A.

    1978-05-01

    Asphalts are present in the Dead Sea basin in three forms: (1) huge blocks, up to 100 tons in weight, composed of extremely pure (>99.99%) solid asphalt occasionally found floating on the lake, (2) veins, seepages, and cavity and fissure fillings in Lower Cretaceous to Holocene rocks, and (3) ozocerite veins on the eastern shore of the lake. Dead Sea asphalts probably have been documented over a longer period of time than any other hydrocarbon deposit--from antiquity to the 19th century. Major uses of asphalt from the Dead Sea have been as an ingredient in the embalming process, for medicinal purposes, for fumigation, and for agriculture. The first known war for control of a hydrocarbon deposit was in the Dead Sea area in 312 B.C. between the Seleucid Syrians and the Nabatean Arabs who lived around the lake. Surface manifestations of asphalt are linked closely to tectonic activity. In the lake itself, the asphalt is associated with diapirs During certain historic periods, tectonic and diapiric activity caused frequent liberation to the Dead Sea surface of semiliquid asphalt associated with large amounts of hydrogen sulfide gas. When the tectonic activity was attenuated, as in the 19th and 20th centuries, the rate of asphalt seepage to the bottom sediments of the Dead Sea was much slower and the asphalt solidified on the lake bottom. The release of asphalt to the surface became much more sporadic, and may have resulted in part from earthquakes. Thus, future asphalt prospecting in the Dead Sea area should be conducted along the boundaries of diapirs or their associated faults.

  1. Monitoring sea level and sea surface temperature trends from ERS satellites

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Knudsen, Per; Beckley, B.

    2002-01-01

    Data from the two ESA satellites ERS-1 and ERS-2 are used in global and regional analysis of sea level and sea surface temperature trends over the last, 7.8 years. T he ERS satellites and in the future the ENVISAT satellite provide unique opportunity for monitoring both changes in sea level and sea...... surface temperature as these satellites are equipped with an altimeter to measure sea level height as well as an along track scanning radiometer (ATSR) to measure the sea surface temperature. Consistent increase in both sea level and sea surface temperatures are found in most parts of the Atlantic Ocean...

  2. Changes in extreme sea-levels in the Baltic Sea

    Directory of Open Access Journals (Sweden)

    Andreia Ribeiro

    2014-04-01

    Full Text Available In a climate change context, changes in extreme sea-levels rather than changes in the mean are of particular interest from the coastal protection point of view. In this work, extreme sea-levels in the Baltic Sea are investigated based on daily tide gauge records for the period 1916–2005 using the annual block maxima approach. Extreme events are analysed based on the generalised extreme value distribution considering both stationary and time-varying models. The likelihood ratio test is applied to select between stationary and non-stationary models for the maxima and return values are estimated from the final model. As an independent and complementary approach, quantile regression is applied for comparison with the results from the extreme value approach. The rates of change in the uppermost quantiles are in general consistent and most pronounced for the northernmost stations.

  3. Integrating out the Dirac sea

    Energy Technology Data Exchange (ETDEWEB)

    Karbstein, Felix

    2009-07-08

    We introduce a new method for dealing with fermionic quantum field theories amenable to a mean-field-type approximation. In this work we focus on the relativistic Hartree approximation. Our aim is to integrate out the Dirac sea and derive a no-sea effective theory'' with positive energy single particle states only. As the derivation of the no-sea effective theory involves only standard Feynman diagrams, our approach is quite general and not restricted to particular space-time dimensions. We develop and illustrate the approach in the ''large N'' limit of the Gross-Neveu model family in 1+1 dimensions. As the Gross-Neveu model has been intensely studied and several analytical solutions are known for this model, it is an ideal testing ground for our no-sea effective theory approach. The chiral Gross-Neveu model, also referred to as 1+1 dimensional Nambu-Jona-Lasinio model, turns out to be of particular interest. In this case, we explicitly derive a consistent effective theory featuring both elementary ''{pi} meson'' fields and (positive energy) ''quark'' fields, starting from a purely fermionic quantum field theory. In the second part of this work, we apply our approach to the Walecka model in 1+1 and 3+1 dimensions. As the Dirac sea caused considerable difficulties in attempts to base nuclear physics on field theoretic models like the Walecka model, mean-field calculations were typically done without the sea. We confront several of these mean-field theory results with our no-sea effective theory approach. The potential of our approach is twofold. While the no-sea effective theory can be utilized to provide new analytical insights in particular parameter regimes, it also sheds new light on more fundamental issues as the explicit emergence of effective, Dirac-sea induced multi-fermion interactions in an effective theory with positive energy states only. (orig.)

  4. Sea Ice Concentration and Extent

    Science.gov (United States)

    Comiso, Josefino C.

    2014-01-01

    Among the most seasonal and most dynamic parameters on the surface of the Earth is sea ice which at any one time covers about 3-6% of the planet. In the Northern Hemisphere, sea ice grows in extent from about 6 x 10(exp 6) sq km to 16 x 10(exp 6) sq km, while in the Southern Hemisphere, it grows from about 3 x 10(exp 6) sq km to about 19 x 10(exp 6) sq km (Comiso, 2010; Gloersen et al., 1992). Sea ice is up to about 2-3 m thick in the Northern Hemisphere and about 1 m thick in the Southern Hemisphere (Wadhams, 2002), and compared to the average ocean depth of about 3 km, it is a relatively thin, fragile sheet that can break due to waves and winds or melt due to upwelling of warm water. Being constantly advected by winds, waves, and currents, sea ice is very dynamic and usually follows the directions of the many gyres in the polar regions. Despite its vast expanse, the sea ice cover was previously left largely unstudied and it was only in recent years that we have understood its true impact and significance as related to the Earths climate, the oceans, and marine life.

  5. Analysis of sea ice dynamics

    Science.gov (United States)

    Zwally, J.

    1988-01-01

    The ongoing work has established the basis for using multiyear sea ice concentrations from SMMR passive microwave for studies of largescale advection and convergence/divergence of the Arctic sea ice pack. Comparisons were made with numerical model simulations and buoy data showing qualitative agreement on daily to interannual time scales. Analysis of the 7-year SMMR data set shows significant interannual variations in the total area of multiyear ice. The scientific objective is to investigate the dynamics, mass balance, and interannual variability of the Arctic sea ice pack. The research emphasizes the direct application of sea ice parameters derived from passive microwave data (SMMR and SSMI) and collaborative studies using a sea ice dynamics model. The possible causes of observed interannual variations in the multiyear ice area are being examined. The relative effects of variations in the large scale advection and convergence/divergence within the ice pack on a regional and seasonal basis are investigated. The effects of anomolous atmospheric forcings are being examined, including the long-lived effects of synoptic events and monthly variations in the mean geostrophic winds. Estimates to be made will include the amount of new ice production within the ice pack during winter and the amount of ice exported from the pack.

  6. Pollution in the Baltic Sea.

    Science.gov (United States)

    Rheinheimer, G

    1998-07-01

    The Baltic Sea is almost totally surrounded by land and therefore more endangered by pollution than other marine areas. The sources of marine pollution are municipal and industrial waste inputs directly into the sea or via rivers, and atmospheric inputs mainly from traffic and agriculture. The increase of inorganic plant nutrients (NH3, NOx, PO4) caused eutrophication and consequent oxygen depletion in coastal bottom waters as well as in the depths of the open sea. In the anoxic sediments, hydrogen sulfide can be produced by protein-decomposing and sulfate-reducing bacteria. The bottom fauna will be destroyed and only H2S tolerant microorganisms can survive. Originating from cellulose manufacturing and from paper mills, large amounts of poisonous chlorinated compounds contaminated the coastal waters of Sweden and Finland until the 1980s. Most of this material is still present in sediments of the central Baltic Sea and can be resuspended by near bottom currents. To reduce pollution and improve the situation in the Baltic Sea, the surrounding countries organized the Helsinki Convention, which came into force on 3.5.1980. The Helsinki Commission (HELCOM) founded in 1974 acts as coordinator and is responsible for the enforcement of the Baltic monitoring program and international research projects. The activities of HELCOM have led to the reduction of dangerous pollutants which in turn has caused the regeneration of flora and fauna in some areas. Further improvements can be expected.

  7. Chemical pollution of northern seas

    International Nuclear Information System (INIS)

    Savinova, T.N.

    1991-01-01

    An extensive review is presented on petroleum and chlorinated hydrocarbon pollution in waters and marine organisms of the North Atlantic and of the North, Baltic, Norwegian, and Barents Seas. Data are presented on the bioaccumulation of those pollutants in the organs and tissues of sea birds and of marine biota at various trophic levels. The effects of pollutants on plankton in northern seas are discussed. Factors affecting the bioaccumulation of toxic substances in fish are also examined. It has been discovered that residual quantities of polychlorinated biphenyls, chlorinated pesticides and their metabolites, and petroleum hydrocarbons are present everywhere at all water levels in northern seas. Of particular concern is the fact that maximum concentrations of contaminants have been recorded in the most productive regions, including shelf and estuary zones, the euphotic zone, and areas of upwelling. Both individual toxic substances and their combinations disrupt normal functioning of ecosystems in northern seas, causing a change in the level of primary production and a decline in fish productivity. Pollutant accumulation in commercially valuable organisms represents a serious threat to human health. 424 refs., 13 figs., 15 tabs

  8. Satellite monitoring of sea surface pollution. [North and Irish Seas

    Science.gov (United States)

    Fielder, G.; Hall, T. S. (Principal Investigator); Telfer, D. J.; Wilson, L.; Fryer, R. J.

    1980-01-01

    Thermal IR data from NASA's Heat Capacity Mapping Mission were used in a study of the feasibility of detecting oil spills in the seas around the UK. The period of observation covered the years 1978/9, in which there were no major spills in the area. A video processor capable of generating false color renderings of any satellite image from eight density levels was used in the synoptic search for spills. Other laboratory equipment, and associated analyses, were used to study the thermal behavior of oil spills on water. Oil spills may appear to be warmer or cooler that the surrounding sea, depending on numerous factors.

  9. Alone by the Sea

    Directory of Open Access Journals (Sweden)

    Zoran Ferić

    2015-06-01

    Full Text Available 1.At first the island is just a sign on a yellow board with a drawing of a vessel and the letters saying “Car Ferry,” then it is a grayish silhouette in the blue of the sea, and then, later still, an acquaintance working on the ferry, who just nods briefly in greeting. Jablanac, ferry port, its pleasant lobby, and then, from the upper deck, a giant rock approaching. That is the object of a year-long desire: the moment of stepping off the boat and smelling the rosemary, diesel and sheep droppings, seeing the sharp rocks looking at the Strait of Senj, coarse limestone in sharp opposition to the signs that say: Benvenuti, Welcome, Willkommen!At home, on the terrace, in the shade of the oleander, there’s no wish to eat. Only swimming trunks are put on and then, barefoot, without a towel or sun-tanning lotion, off to the beach.“Why won’t you eat something?” grandma asks.She knows that there’s an exciting world waiting out there, but she knows nothing of the details. All friends went on a boat trip. And suddenly one step from the shade of a path covered with oleanders and acacias leads into the burning sun of the afternoon. The light screams, just like children in the water, just like white objects that radiate as if there are some powerful light bulbs within. The feeling of freedom of someone who has just arrived in a foreign place and can now do anything. There’s no one familiar on the beach, they all got in the boat and left. The seafront leading to the camp is full of people, naked children with dirty faces licking ice cream, young families pushing strollers, groups of teenagers who have just woken up from their last night’s party. But there’s no one that must be greeted. The feeling of freedom that’s at the same time close to death. Suddenly, all paths are open. That there are no obligations or friends waiting, this afternoon, until they come back, is a complete boon.

  10. Vulnerability of marginal seas to sea level rise

    Science.gov (United States)

    Gomis, Damia; Jordà, Gabriel

    2017-04-01

    Sea level rise (SLR) is a serious thread for coastal areas and has a potential negative impact on society and economy. SLR can lead for instance to land loss, beach reduction, increase of the damage of marine storms on coastal infrastructures and to the salinization of underground water streams. It is well acknowledged that future SLR will be inhomogeneous across the globe, with regional differences of up to 100% with respect to global mean sea level (GMSL). Several studies have addressed the projections of SLR at regional scale, but most of them are based on global climate models (GCMs) that have a relatively coarse spatial resolution (>1°). In marginal seas this has proven to be a strong limitation, as their particular configurations require spatial resolutions that are not reachable by present GCMs. A paradigmatic case is the Mediterranean Sea, connected to the global ocean through the Strait of Gibraltar, a narrow passage of 14 km width. The functioning of the Mediterranean Sea involves a variety of processes including an overturning circulation, small-scale convection and a rich mesoscale field. Moreover, the long-term evolution of Mediterranean sea level has been significantly different from the global mean during the last decades. The observations of present climate and the projections for the next decades have lead some authors to hypothesize that the particular characteristics of the basin could allow Mediterranean mean sea level to evolve differently from the global mean. Assessing this point is essential to undertake proper adaptation strategies for the largely populated Mediterranean coastal areas. In this work we apply a new approach that combines regional and global projections to analyse future SLR. In a first step we focus on the quantification of the expected departures of future Mediterranean sea level from GMSL evolution and on the contribution of different processes to these departures. As a result we find that, in spite of its particularities

  11. Sea ice dynamics across the Mid-Pleistocene transition in the Bering Sea.

    Science.gov (United States)

    Detlef, H; Belt, S T; Sosdian, S M; Smik, L; Lear, C H; Hall, I R; Cabedo-Sanz, P; Husum, K; Kender, S

    2018-03-05

    Sea ice and associated feedback mechanisms play an important role for both long- and short-term climate change. Our ability to predict future sea ice extent, however, hinges on a greater understanding of past sea ice dynamics. Here we investigate sea ice changes in the eastern Bering Sea prior to, across, and after the Mid-Pleistocene transition (MPT). The sea ice record, based on the Arctic sea ice biomarker IP 25 and related open water proxies from the International Ocean Discovery Program Site U1343, shows a substantial increase in sea ice extent across the MPT. The occurrence of late-glacial/deglacial sea ice maxima are consistent with sea ice/land ice hysteresis and land-glacier retreat via the temperature-precipitation feedback. We also identify interactions of sea ice with phytoplankton growth and ocean circulation patterns, which have important implications for glacial North Pacific Intermediate Water formation and potentially North Pacific abyssal carbon storage.

  12. Respiration in neonate sea turtles.

    Science.gov (United States)

    Price, Edwin R; Paladino, Frank V; Strohl, Kingman P; Santidrián T, Pilar; Klann, Kenneth; Spotila, James R

    2007-03-01

    The pattern and control of respiration is virtually unknown in hatchling sea turtles. Using incubator-raised turtles, we measured oxygen consumption, frequency, tidal volume, and minute volume for leatherback (Dermochelys coriacea) and olive ridley (Lepidochelys olivacea) turtle hatchlings for the first six days after pipping. In addition, we tested the hatchlings' response to hypercapnic, hyperoxic, and hypoxic challenges over this time period. Hatchling sea turtles generally showed resting ventilation characteristics that are similar to those of adults: a single breath followed by a long respiratory pause, slow frequency, and high metabolic rate. With hypercapnic challenge, both species responded primarily by elevating respiratory frequency via a decrease in the non-ventilatory period. Leatherback resting tidal volume increased with age but otherwise, neither species' resting respiratory pattern nor response to gas challenge changed significantly over the first few days after hatching. At the time of nest emergence, sea turtles have achieved a respiratory pattern that is similar to that of actively diving adults.

  13. Oil and the Caspian Sea

    International Nuclear Information System (INIS)

    Mohammad Poure Daryaei, N.

    2000-01-01

    Caspian Sea is the biggest lake in the world. It is almost F-shape and located between five Countries of Iran, Turkmenistan, Russia, Azarbayjohn, Ghazaghestan. Un fortunately, in the different region of the sea there are highly contaminated oil, in addition with other source of pollutants such as: agricultural, industrial and domestic pollution, which causes to eliminate the natural habitats of aquatic life and thus, the Caspian sea with all of the valuable natural sources of foods and energy is close to be destroyed. This paper studies the pollution by oil industry which causes the elimination of aquatic life and natural ecosystem, as well as, necessary plan to over come the present situation

  14. GHRSST Level 4 DMI_OI North Sea and Baltic Sea Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis by the Danish...

  15. 16 MW under the seas

    International Nuclear Information System (INIS)

    Mary, Olivier

    2014-01-01

    This article presents the Nemo project (Nemo stands for New Energy for Martinique and Overseas) and its precursor project, Ner 300, developed in cooperation between Akuo Energy and DCNS, and which is financed by the European Bank for Investment. These projects aim at exploiting sea thermal energy. Ner 300 will exploit the 20 degree difference between surface waters (25 C) and deep waters (5 C at 1.000 m under sea level). The article evokes works performed by DCNS to develop a prototype near the Reunion Island. The principle and operation are briefly described, and technological challenges are outlined

  16. Black Sea coastal forecasting system

    Directory of Open Access Journals (Sweden)

    A. I. Kubryakov

    2012-03-01

    Full Text Available The Black Sea coastal nowcasting and forecasting system was built within the framework of EU FP6 ECOOP (European COastalshelf sea OPerational observing and forecasting system project for five regions: the south-western basin along the coasts of Bulgaria and Turkey, the north-western shelf along the Romanian and Ukrainian coasts, coastal zone around of the Crimea peninsula, the north-eastern Russian coastal zone and the coastal zone of Georgia. The system operates in the real-time mode during the ECOOP project and afterwards. The forecasts include temperature, salinity and current velocity fields. Ecosystem model operates in the off-line mode near the Crimea coast.

  17. Deep-sea genetic resources

    OpenAIRE

    Desbruyere, D; Arnaud-haond, Sophie; Fabri, Marie-claire; Guezennec, Jean; Querellou, Joel

    2007-01-01

    Two third of our Planet are covered by oceans more than 3,000m deep (~ 307 millions km2) and the mean depth of the sea is approximately 3,800m. The volume of the deep ocean (aphotic) is about 1,280 Millions of km3 while the volume of terrestrial ecosystems is only 125 Millions of km3. Therefore, the deep-sea ecosystem is by far the largest complex biome on the Earth. However, it suffers from a general disinterest of the public and decision makers due to its remoteness and inaccessibility. Edw...

  18. Chemical oceanography of the Arabian Sea Part iv Laccadive sea

    Digital Repository Service at National Institute of Oceanography (India)

    SenGupta, R.; Moraes, C.; Kureishy, T.W.; Sankaranarayanan, V.N.; Jana, T.K.; Naqvi, S.W.A.; Rajagopal, M.D.

    Data collected during the 10th (October 1976) and 31st (March-April 1978) cruises of R V Gaveshani suggest that water movements, considered typical of island-arc regions, are responsible for high levels of productivity observed in the Laccadive Sea...

  19. 2010 USGS Lidar: Salton Sea (CA)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The USGS Salton Sea project encompasses a 5-kilometer buffer around the Salton Sea, California. Dewberry classified LiDAR for a project boundary that touches 623...

  20. Quarterly Fishery Surveys - Salton Sea [ds428

    Data.gov (United States)

    California Natural Resource Agency — In the spring of 2003, California Department of Fish and Game (CDFG) personnel began quarterly sampling of Salton Sea fish at fourteen stations around the sea, as...

  1. Arctic Sea Ice Freeboard and Thickness

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides measurements of sea ice freeboard and sea ice thickness for the Arctic region. The data were derived from measurements made by from the Ice,...

  2. Quarterly Fishery Surveys - Salton Sea [ds428

    Data.gov (United States)

    California Department of Resources — In the spring of 2003, California Department of Fish and Game (CDFG) personnel began quarterly sampling of Salton Sea fish at fourteen stations around the sea, as...

  3. Temperature, salinity, and nutrients data collected from North Atlantic Ocean, White Sea, Mediterranean Sea, Black Sea, and Sea of Azov from 1924-03-19 to 1989-11-19 by multiple Soviet Union institutes (NODC Accession 0077413)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, and nutrients data collected from North Atlantic Ocean, White Sea, Mediterranean Sea, Black Sea, and Sea of Azov from 1924-03-19 to 1989-11-19...

  4. The German Sea Rescue Service (SAR).

    Science.gov (United States)

    2002-01-01

    The German Sea Rescue Service (GSRS) history, organisation and operations are presented. The institution was founded in 1865 to provide sea rescue services for the German coasts in the North Sea and in the Baltic Sea. Its fleet counts 61 vessels based in 54 stations of the service. In 2001, the rescue crafts were called for assistance 2428 times and 207 lives were saved. The service is supported by voluntary donations.

  5. Mangrove dieback during fluctuating sea levels

    OpenAIRE

    Lovelock, Catherine E.; Feller, Ilka C.; Reef, Ruth; Hickey, Sharyn; Ball, Marilyn C.

    2017-01-01

    Recent evidence indicates that climate change and intensification of the El Ni?o Southern Oscillation (ENSO) has increased variation in sea level. Although widespread impacts on intertidal ecosystems are anticipated to arise from the sea level seesaw associated with climate change, none have yet been demonstrated. Intertidal ecosystems, including mangrove forests are among those ecosystems that are highly vulnerable to sea level rise, but they may also be vulnerable to sea level variability a...

  6. Modeling Gas Dynamics in California Sea Lions

    Science.gov (United States)

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Modeling Gas Dynamics in California Sea Lions Andreas...California sea lions . The model will be calibrated against measured arterial and venous PO2 levels from California sea lions , and estimate the error between...existing model with new species-specific parameter estimates for California sea lions . Aim 2: Compare estimated and measured arterial and venous

  7. IAHR List of Sea Parameters

    DEFF Research Database (Denmark)

    Frigaard, Peter; Helm-Petersen, J; Klopman, G.

    1997-01-01

    A Working Group on multidirectional waves formed by the International Association for Hydraulic Research has proposed an update of the IAHR List of Sea State Parameters from 1986 in the part concerning directional. Especially wave structure interaction with reflection of the waves have been treated....

  8. A Deep-Sea Simulation.

    Science.gov (United States)

    Montes, Georgia E.

    1997-01-01

    Describes an activity that simulates exploration techniques used in deep-sea explorations and teaches students how this technology can be used to take a closer look inside volcanoes, inspect hazardous waste sites such as nuclear reactors, and explore other environments dangerous to humans. (DDR)

  9. Mind the gap in SEA

    DEFF Research Database (Denmark)

    Larsen, Sanne Vammen; Kørnøv, Lone; Wejs, Anja

    2012-01-01

    This article takes its point of departure in two approaches to integrating climate change into Strategic Environmental Assessment (SEA): Mitigation and adaptation, and in the fact that these, as well as the synergies between them and other policy areas, are needed as part of an integrated assessm...

  10. Ploughing the deep sea floor.

    Science.gov (United States)

    Puig, Pere; Canals, Miquel; Company, Joan B; Martín, Jacobo; Amblas, David; Lastras, Galderic; Palanques, Albert

    2012-09-13

    Bottom trawling is a non-selective commercial fishing technique whereby heavy nets and gear are pulled along the sea floor. The direct impact of this technique on fish populations and benthic communities has received much attention, but trawling can also modify the physical properties of seafloor sediments, water–sediment chemical exchanges and sediment fluxes. Most of the studies addressing the physical disturbances of trawl gear on the seabed have been undertaken in coastal and shelf environments, however, where the capacity of trawling to modify the seafloor morphology coexists with high-energy natural processes driving sediment erosion, transport and deposition. Here we show that on upper continental slopes, the reworking of the deep sea floor by trawling gradually modifies the shape of the submarine landscape over large spatial scales. We found that trawling-induced sediment displacement and removal from fishing grounds causes the morphology of the deep sea floor to become smoother over time, reducing its original complexity as shown by high-resolution seafloor relief maps. Our results suggest that in recent decades, following the industrialization of fishing fleets, bottom trawling has become an important driver of deep seascape evolution. Given the global dimension of this type of fishery, we anticipate that the morphology of the upper continental slope in many parts of the world’s oceans could be altered by intensive bottom trawling, producing comparable effects on the deep sea floor to those generated by agricultural ploughing on land.

  11. Chaetognatha of the Andaman Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, V.R.; Achuthankutty, C.T.; Nair, S.R.S.; Madhupratap, M.

    Chaetognatha of the Andaman Sea were studied during 51 and 52 cruises of R.V Gaveshani (Jan to Feb 1979) The area between southeast of Andaman island and north of Nicobar island had relatively higher density Total population of chaetognaths ranged...

  12. Climate change challenges for SEA

    DEFF Research Database (Denmark)

    Larsen, Sanne Vammen

    This paper takes a theoretical perspective on the challenges that climate changes pose for SEA. The theoretical framework used is the sociologist Ulrich Beck’s theory of risk society and the aspects that characterise this society. Climate change is viewed as a risk, and the theory is used to derive...

  13. Global sea turtle conservation successes.

    Science.gov (United States)

    Mazaris, Antonios D; Schofield, Gail; Gkazinou, Chrysoula; Almpanidou, Vasiliki; Hays, Graeme C

    2017-09-01

    We document a tendency for published estimates of population size in sea turtles to be increasing rather than decreasing across the globe. To examine the population status of the seven species of sea turtle globally, we obtained 299 time series of annual nesting abundance with a total of 4417 annual estimates. The time series ranged in length from 6 to 47 years (mean, 16.2 years). When levels of abundance were summed within regional management units (RMUs) for each species, there were upward trends in 12 RMUs versus downward trends in 5 RMUs. This prevalence of more upward than downward trends was also evident in the individual time series, where we found 95 significant increases in abundance and 35 significant decreases. Adding to this encouraging news for sea turtle conservation, we show that even small sea turtle populations have the capacity to recover, that is, Allee effects appear unimportant. Positive trends in abundance are likely linked to the effective protection of eggs and nesting females, as well as reduced bycatch. However, conservation concerns remain, such as the decline in leatherback turtles in the Eastern and Western Pacific. Furthermore, we also show that, often, time series are too short to identify trends in abundance. Our findings highlight the importance of continued conservation and monitoring efforts that underpin this global conservation success story.

  14. Increased CO2 uptake due to sea ice growth and decay in the Nordic Seas

    DEFF Research Database (Denmark)

    Rysgaard, S.; Bendtsen, J.; Pedersen, L. T.

    2009-01-01

    uptake in the Nordic Seas is currently unknown. We present evidence from 50 localities in the Arctic Ocean that dissolved inorganic carbon is rejected together with brine from growing sea ice and that sea ice melting during summer is rich in carbonates. Model calculations show that melting of sea ice......The uptake rates of atmospheric CO2 in the Nordic Seas are among the highest in the world's oceans. This has been ascribed mainly to a strong biological drawdown, but chemical processes within the sea ice itself have also been suggested to play a role. The importance of sea ice for the carbon...

  15. Historical Bibliography of Sea Mine Warfare

    Science.gov (United States)

    1976-01-01

    609. Murder at Sea and the Blockade of German Experts; Spector, Vol. CLXIII, 11. Nov. 24, 1939; London. pg. 729. (Murray), Army and Navy Journal, Vol...War at Sea: Death for the Magpie ; Time, Vol. LVI, No. 16, Oct. 16, 1950; 7. New York. pg. 27. The War at Sea: Going In; Time, Vol. LVI, No. 18, Oct. 30

  16. Messinian events in the Black Sea

    NARCIS (Netherlands)

    van Baak, Christiaan G C; Radionova, Eleanora P.; Golovina, Larisa A.; Raffi, Isabella; Kuiper, Klaudia F.; Vasiliev, Iuliana; Krijgsman, Wout

    2015-01-01

    Past hydrological interactions between the Mediterranean Sea and Black Sea are poorly resolved due to complications in establishing a high-resolution time frame for the Black Sea. We present a new greigite-based magnetostratigraphic age model for the Mio-Pliocene deposits of DSDP Hole 380/380A,

  17. PECULIARITIES OF CONTAMINATION OF THE BLACK SEA

    Directory of Open Access Journals (Sweden)

    George O. Biliavskiy

    2009-04-01

    Full Text Available  Article is devoted to meaningfulness estimation of some factors in forming ecological conditions in regions of the Black Sea. Comparative estimation of anthropogenic contamination degree of sea regions environment considered. The regions the most unhappy in ecological attitude are defined, that allows to mark first and foremost arrangements on improvement of ecological situation of the Black Sea.

  18. OW NASA SeaWIFS Ocean Color

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The dataset contains satellite-derived sea-surface ocean color (chlorophyll-a) measurements collected by means of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS)...

  19. Parasites in the Wadden Sea food web

    NARCIS (Netherlands)

    Thieltges, D.W.; Engelsma, M.Y.; Wendling, C.C.; Wegner, K.M.

    2013-01-01

    While the free-living fauna of the Wadden Sea has received much interest, little is known on the distribution and effects of parasites in the Wadden Sea food web. However, recent studies on this special type of trophic interaction indicate a high diversity of parasites in the Wadden Sea and suggest

  20. 50 CFR 223.205 - Sea turtles.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Sea turtles. 223.205 Section 223.205... Threatened Marine and Anadromous Species § 223.205 Sea turtles. (a) The prohibitions of section 9 of the Act (16 U.S.C. 1538) relating to endangered species apply to threatened species of sea turtle, except as...

  1. Vision in the deep sea.

    Science.gov (United States)

    Warrant, Eric J; Locket, N Adam

    2004-08-01

    The deep sea is the largest habitat on earth. Its three great faunal environments--the twilight mesopelagic zone, the dark bathypelagic zone and the vast flat expanses of the benthic habitat--are home to a rich fauna of vertebrates and invertebrates. In the mesopelagic zone (150-1000 m), the down-welling daylight creates an extended scene that becomes increasingly dimmer and bluer with depth. The available daylight also originates increasingly from vertically above, and bioluminescent point-source flashes, well contrasted against the dim background daylight, become increasingly visible. In the bathypelagic zone below 1000 m no daylight remains, and the scene becomes entirely dominated by point-like bioluminescence. This changing nature of visual scenes with depth--from extended source to point source--has had a profound effect on the designs of deep-sea eyes, both optically and neurally, a fact that until recently was not fully appreciated. Recent measurements of the sensitivity and spatial resolution of deep-sea eyes--particularly from the camera eyes of fishes and cephalopods and the compound eyes of crustaceans--reveal that ocular designs are well matched to the nature of the visual scene at any given depth. This match between eye design and visual scene is the subject of this review. The greatest variation in eye design is found in the mesopelagic zone, where dim down-welling daylight and bio-luminescent point sources may be visible simultaneously. Some mesopelagic eyes rely on spatial and temporal summation to increase sensitivity to a dim extended scene, while others sacrifice this sensitivity to localise pinpoints of bright bioluminescence. Yet other eyes have retinal regions separately specialised for each type of light. In the bathypelagic zone, eyes generally get smaller and therefore less sensitive to point sources with increasing depth. In fishes, this insensitivity, combined with surprisingly high spatial resolution, is very well adapted to the

  2. Management of the Wadden Sea

    Science.gov (United States)

    Wolff, W. J.; Zijlstra, J. J.

    1980-03-01

    The Wadden Sea situated along the North Sea coasts of Denmark, the Federal Republic of Germany and The Netherlands represents one of the world's largest bar-built type of estuaries. The area is a typical sedimentation and mineralization basin, with a large influx of organic matter from the adjoining North Sea, consequently a delicate oxygen balance and a rich benthic macrofauna, poor in species, which serves as food for juveniles of some commercially important North Sea fishes and for large numbers of migrating and wintering waders and waterfowl. Past and present activities of the human society in the area include fisheries (mainly for shrimp and mussels, semi-culture), shipping, land reclamation, recreation, dredging for sand and shells, and waste discharge from industries and human communities. Until the present these activities, although sometimes conflicting, did not fundamentally affect the area and its biota (pollution excluded), but future claims, including the construction of large deep-sea harbours, drilling for natural gas and oil, large-scale land reclamation and increased industrialization etc., might gradually induce degradation. For instance, area reduction by continued land reclamation could lead to irreversible losses of specific biotopes (e. g. salt-marshes, mud-flats), which could affect the size of bird and fish populations in a much wider region. Increased pollution, which has already inflicted damage on bird and seal populations, could reduce the fauna and hence the value of the area as a natural sanctuary. In the event of a proposal for a new human activity in the area, the present standing practice in the countries concerned requires an evaluation of its safety and economic aspects and its environmental impact. However, the various plans are considered separately and there is a general need for integrated management of the area.

  3. Thermal biology of sea snakes and sea kraits.

    Science.gov (United States)

    Heatwole, Harold; Grech, Alana; Monahan, John F; King, Susan; Marsh, Helene

    2012-08-01

    Temperature probably had no direct effect on the evolution of sea kraits within their center of origin, a geologically stable thermal zone straddling the equator, but may have indirectly affected expansions and contractions in distributions beyond that zone through global fluctuations that caused alternation of higher and lower sea levels. The northern limit of the Laticauda colubrina complex seems to be the 20°C isotherm; in the south, the range does not reach that isotherm because there is no land (also a habitat requirement of sea kraits) within the zone of suitable temperature. The relationship of temperature to the pattern of geographic variation in morphology supports either the hypothesis of peripheral convergence or the developmental hypothesis but does not distinguish between them. Quadratic surfaces relating cumulative scores for coloration and morphological characters to global position showed a strong latitudinal component and an even stronger longitudinal one in which the direction of the latitudinal effect was reversed between east and west. A multivariate analysis revealed that while morphological characters vary significantly by location and climate when tested separately, when the influence of location on morphology is taken into account, no residual relationship between climate and morphology remains. Most marine snakes have mean upper temperature tolerances between 39°C and 40°C and operate at temperatures much nearer their upper thermal limits than their lower limits but still avoid deleterious extremes by diving from excessively hot water to deeper, cooler strata, and by surfacing when water is cold. At the surface in still water in sunlight, Pelamis can maintain its body temperature slightly above that of the water, but whether this is significant in nature is questionable. As temperature falls below 18-20°C, survival time is progressively reduced, accompanied by the successive occurrence of cessation of feeding, cessation of swimming, and

  4. Distribution characteristics of marine litter on the sea bed of the East China Sea and the South Sea of Korea

    Science.gov (United States)

    Lee, Dae-In; Cho, Hyeon-Seo; Jeong, Sun-Beom

    2006-10-01

    The types, quantities, and distribution of marine litter found on the sea bed of the East China Sea and the South Sea of Korea are surveyed. Surveys were evaluated using bottom trawl nets during 1996-2005 cruises. Mean distribution densities were high in coastal seas, especially in the South Sea of Korea offshore from Yeosu, with 109.8 kg km -2, and low in the East China Sea, with densities of 30.6 kg km -2. Fishing gear, such as pots, nets, octopus jars, and fishing lines, accounted for about 42-72% and 37-62% of litter items in the East China Sea and the South Sea of Korea, respectively, whereas the contributions of rubber, vinyl, metal, plastic, glass, wood, and clothing were below 30% mainly. Rope and drum composition fluctuated greatly, between 54% and 0%. Eel and net pots dominated the marine debris of the South Sea of Korea, and some vinyl, plastics, and fishing gear made in Korea, China, and Japan were collected in abundance in the East China Sea. Fishing gear was probably discarded into the sea, deliberately or inadvertently, by fishing operations. A comprehensive joint approach by Korea, China, and Japan is needed for the continuous monitoring of input sources, the actual conditions, and the behavior of marine litter for protection against litter pollution and fisheries resource management in this area.

  5. Temperature, Salinity, Oxygen, Phosphate, pH and Alkalinity data collected in the North Atlantic Ocean, Baltic Sea, Barents Sea, Greenland Sea, North Sea, Norwegian Sea and White Sea from R/Vs Artemovsk, Atlantida, Okeanograf, Professor Rudovits, and ice observations, 1957 - 1995 (NODC Accession 0073674)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, Salinity, Oxygen, Phosphate, pH and Alkalinity data collected in the North Atlantic Ocean, Baltic Sea, Barents Sea, Greenland Sea, North Sea, Norwegian...

  6. Seasonal sea ice cover during the warm Pliocene: Evidence from the Iceland Sea (ODP Site 907)

    Science.gov (United States)

    Clotten, Caroline; Stein, Ruediger; Fahl, Kirsten; De Schepper, Stijn

    2018-01-01

    Sea ice is a critical component in the Arctic and global climate system, yet little is known about its extent and variability during past warm intervals, such as the Pliocene (5.33-2.58 Ma). Here, we present the first multi-proxy (IP25, sterols, alkenones, palynology) sea ice reconstructions for the Late Pliocene Iceland Sea (ODP Site 907). Our interpretation of a seasonal sea ice cover with occasional ice-free intervals between 3.50-3.00 Ma is supported by reconstructed alkenone-based summer sea surface temperatures. As evidenced from brassicasterol and dinosterol, primary productivity was low between 3.50 and 3.00 Ma and the site experienced generally oligotrophic conditions. The East Greenland Current (and East Icelandic Current) may have transported sea ice into the Iceland Sea and/or brought cooler and fresher waters favoring local sea ice formation. Between 3.00 and 2.40 Ma, the Iceland Sea is mainly sea ice-free, but seasonal sea ice occurred between 2.81 and 2.74 Ma. Sea ice extending into the Iceland Sea at this time may have acted as a positive feedback for the build-up of the Greenland Ice Sheet (GIS), which underwent a major expansion ∼2.75 Ma. Thereafter, most likely a stable sea ice edge developed close to Greenland, possibly changing together with the expansion and retreat of the GIS and affecting the productivity in the Iceland Sea.

  7. On the Sea, From the Sea, Of the Sea: The Physics of maritime Governance

    Science.gov (United States)

    James, Royce; Page, Eric

    2014-03-01

    The United States Coast Guard Academy Physics Section is proud to present our initial conceptions of ``On the Sea, From the Sea, Of the Sea: The Physics of Maritime Governance,'' a program funded by an APS Outreach Grant in 2013. In our classes, the Physics Section has focused on active student engagement for the past ten years. Recently, we have refined our program to make heavy use of Interactive Lecture Demonstrations (ILDs) and our own highly interactive adaptation which we call Interactive Lecture Labs (ILLs). ``On the Sea'' is a unique opportunity to investigate their use in a different learning modality from our standard college level military academic use. Multigenerational science, technology, engineering, and mathematics (STEM) projects are a prolific source of academic discourse, while learning through play has been touted as an effective learning tool. We plan to investigate group and individual participation, intragroup communication, demographics, and prior skill (or education) in comparison to outcomes in learning objectives through projects designed to educate the Coast Guard Academy and surrounding community on the physics of the Coast Guard's missions. Progress on the lab and demonstration designs, community participation, and our emerging ILL and ILD pedagogical methods, will be reported.

  8. Deglacial sea level history of the East Siberian Sea and Chukchi Sea margins

    Science.gov (United States)

    Cronin, Thomas M.; O'Regan, Matt; Pearce, Christof; Gemery, Laura; Toomey, Michael; Semiletov, Igor

    2017-01-01

    Deglacial (12.8–10.7 ka) sea level history on the East Siberian continental shelf and upper continental slope was reconstructed using new geophysical records and sediment cores taken during Leg 2 of the 2014 SWERUS-C3 expedition. The focus of this study is two cores from Herald Canyon, piston core SWERUS-L2-4-PC1 (4-PC1) and multicore SWERUS-L2-4-MC1 (4-MC1), and a gravity core from an East Siberian Sea transect, SWERUS-L2-20-GC1 (20-GC1). Cores 4-PC1 and 20-GC were taken at 120 and 115 m of modern water depth, respectively, only a few meters above the global last glacial maximum (LGM;  ∼  24 kiloannum or ka) minimum sea level of  ∼  125–130 meters below sea level (m b.s.l.). Using calibrated radiocarbon ages mainly on molluscs for chronology and the ecology of benthic foraminifera and ostracode species to estimate paleodepths, the data reveal a dominance of river-proximal species during the early part of the Younger Dryas event (YD, Greenland Stadial GS-1) followed by a rise in river-intermediate species in the late Younger Dryas or the early Holocene (Preboreal) period. A rapid relative sea level rise beginning at roughly 11.4 to 10.8 ka ( ∼  400 cm of core depth) is indicated by a sharp faunal change and unconformity or condensed zone of sedimentation. Regional sea level at this time was about 108 m b.s.l. at the 4-PC1 site and 102 m b.s.l. at 20-GC1. Regional sea level near the end of the YD was up to 42–47 m lower than predicted by geophysical models corrected for glacio-isostatic adjustment. This discrepancy could be explained by delayed isostatic adjustment caused by a greater volume and/or geographical extent of glacial-age land ice and/or ice shelves in the western Arctic Ocean and adjacent Siberian land areas.

  9. Deglacial sea level history of the East Siberian Sea and Chukchi Sea margins

    Science.gov (United States)

    Cronin, Thomas M.; O'Regan, Matt; Pearce, Christof; Gemery, Laura; Toomey, Michael; Semiletov, Igor; Jakobsson, Martin

    2017-09-01

    Deglacial (12.8-10.7 ka) sea level history on the East Siberian continental shelf and upper continental slope was reconstructed using new geophysical records and sediment cores taken during Leg 2 of the 2014 SWERUS-C3 expedition. The focus of this study is two cores from Herald Canyon, piston core SWERUS-L2-4-PC1 (4-PC1) and multicore SWERUS-L2-4-MC1 (4-MC1), and a gravity core from an East Siberian Sea transect, SWERUS-L2-20-GC1 (20-GC1). Cores 4-PC1 and 20-GC were taken at 120 and 115 m of modern water depth, respectively, only a few meters above the global last glacial maximum (LGM; ˜ 24 kiloannum or ka) minimum sea level of ˜ 125-130 meters below sea level (m b.s.l.). Using calibrated radiocarbon ages mainly on molluscs for chronology and the ecology of benthic foraminifera and ostracode species to estimate paleodepths, the data reveal a dominance of river-proximal species during the early part of the Younger Dryas event (YD, Greenland Stadial GS-1) followed by a rise in river-intermediate species in the late Younger Dryas or the early Holocene (Preboreal) period. A rapid relative sea level rise beginning at roughly 11.4 to 10.8 ka ( ˜ 400 cm of core depth) is indicated by a sharp faunal change and unconformity or condensed zone of sedimentation. Regional sea level at this time was about 108 m b.s.l. at the 4-PC1 site and 102 m b.s.l. at 20-GC1. Regional sea level near the end of the YD was up to 42-47 m lower than predicted by geophysical models corrected for glacio-isostatic adjustment. This discrepancy could be explained by delayed isostatic adjustment caused by a greater volume and/or geographical extent of glacial-age land ice and/or ice shelves in the western Arctic Ocean and adjacent Siberian land areas.

  10. Deglacial sea level history of the East Siberian Sea and Chukchi Sea margins

    Directory of Open Access Journals (Sweden)

    T. M. Cronin

    2017-09-01

    Full Text Available Deglacial (12.8–10.7 ka sea level history on the East Siberian continental shelf and upper continental slope was reconstructed using new geophysical records and sediment cores taken during Leg 2 of the 2014 SWERUS-C3 expedition. The focus of this study is two cores from Herald Canyon, piston core SWERUS-L2-4-PC1 (4-PC1 and multicore SWERUS-L2-4-MC1 (4-MC1, and a gravity core from an East Siberian Sea transect, SWERUS-L2-20-GC1 (20-GC1. Cores 4-PC1 and 20-GC were taken at 120 and 115 m of modern water depth, respectively, only a few meters above the global last glacial maximum (LGM;  ∼  24 kiloannum or ka minimum sea level of  ∼  125–130 meters below sea level (m b.s.l.. Using calibrated radiocarbon ages mainly on molluscs for chronology and the ecology of benthic foraminifera and ostracode species to estimate paleodepths, the data reveal a dominance of river-proximal species during the early part of the Younger Dryas event (YD, Greenland Stadial GS-1 followed by a rise in river-intermediate species in the late Younger Dryas or the early Holocene (Preboreal period. A rapid relative sea level rise beginning at roughly 11.4 to 10.8 ka ( ∼  400 cm of core depth is indicated by a sharp faunal change and unconformity or condensed zone of sedimentation. Regional sea level at this time was about 108 m b.s.l. at the 4-PC1 site and 102 m b.s.l. at 20-GC1. Regional sea level near the end of the YD was up to 42–47 m lower than predicted by geophysical models corrected for glacio-isostatic adjustment. This discrepancy could be explained by delayed isostatic adjustment caused by a greater volume and/or geographical extent of glacial-age land ice and/or ice shelves in the western Arctic Ocean and adjacent Siberian land areas.

  11. Sea Cucumber (Holothuroidea Species of Turkey

    Directory of Open Access Journals (Sweden)

    Mehmet AYDIN

    2016-11-01

    Full Text Available There are nearly 1200 sea cucumber species in the world oceans, while only 37 species from Holothuroidea class lives in the Mediterranean Sea. This preliminary study aims identification sea cucumbers species of the Turkish waters. The sea cucumber samples used in this study were obtained from a series of different studies between the years of 2008 and 2014. Identification of the species are mainly based on the morphometric characteristics while some of species are determined from their calcareous spicules. Eight sea species were identified in this research which are; Holothuria tubulosa, Holothuria polii, Holothuria mammata, Holothuria (Platyperona sanctori, Holothuria forskali, Stichopus regalis, Synaptula reciprocans and Stereoderma kirschbergi. There are limited number of studies in the literature focusing on the identification of the sea cucumber species spread in our seas. Therefore, this study is believed to play an important role in guiding future researches.

  12. Review of critical factors for SEA implementation

    DEFF Research Database (Denmark)

    Zhang, Jie; Christensen, Per; Kørnøv, Lone

    2013-01-01

    The implementation process involved in translating Strategic Environmental Assessment (SEA) intention into action is vital to an effective SEA. Many factors influence implementation and thus the effectiveness of an SEA. Empirical studies have identified and documented some factors influencing...... the implementation of an SEA. This research is fragmented, however, and it is still not clear what are the most critical factors of effective SEA performance, and how these relate to different stages of the implementation process or other contextual circumstances. The paper takes its point of departure...... tracing the cause and effect is difficult. The pervasiveness of contextual and general factors also clearly suggests that there is no single way to put SEA into practice. The paper identifies some of the critical factors for effective SEA implementation, but further research is still needed to conclude...

  13. Spatial patterns in abundance, taxonomic composition and carbon biomass of nano- and microphytoplankton in Subarctic and Arctic Seas

    Science.gov (United States)

    Crawford, David W.; Cefarelli, Adrián O.; Wrohan, Ian A.; Wyatt, Shea N.; Varela, Diana E.

    2018-03-01

    In the summers of 2007 and 2008, we studied assemblages of nano- and microphytoplankton from the subsurface chlorophyll maximum (SCM) across five broad oceanographic domains in the seas surrounding northern North America. These domains are the eastern Subarctic North Pacific (ESNP), Bering and Chukchi Seas (BE-CH), Beaufort Sea and Canada Basin (BS-CB), Canadian Arctic Archipelago (CAA), and Baffin Bay and Labrador Sea (BB-LS). Average abundance and total carbon biomass (C) of phytoplankton (>2 μm) varied ∼10-fold and ∼20-fold, respectively, across the five domains. In the BE-CH, CAA and BB-LS, diatoms averaged 35-70% and dinoflagellates 11-45% of total phytoplankton C (>2 μm), whereas in the ESNP and BS-CB, unidentified flagellates/coccoids (2-8 μm) represented a greater proportion of total C (27% and 39% respectively) than in the other domains. In the BE-CH and BB-LS, phytoplankton C (>2 μm) was dominated by dinoflagellates of the genus Gymnodinium, centric diatoms including Thalassiosira spp. and Chaetoceros spp., unidentified flagellates/coccoids (2-8 μm), and cryptomonads. In contrast, diatoms such as Thalassiosira spp. and its resting spores dominated C in the CAA, with dinoflagellates being less significant than in the BE-CH and BB-LS. Unidentified flagellates/coccoids (2-8 μm), Gymnodinium spp., and cryptomonads dominated in the ESNP, and particularly in the BS-CB, where diatoms contributed only 18% of the very low levels of total phytoplankton C (>2 μm). Phytoplankton C (>2 μm) to chlorophyll a ratios (phyto C:chl a) averaged only 31 g C g chl a-1 in the oligotrophic BS-CB domain, and 51-150 g C g chl a-1 in the other domains, whereas ratios of biogenic silica to phytoplankton C (>2 μm) (bSi:phyto C) were lowest in the eastern domains. Estimates of phytoplankton C were highly sensitive to the choice of C to cell volume equations (C:vol) adopted in the calculations, particularly in diatom-rich areas. This study highlights how diatoms and

  14. Variability and Trends in Sea Ice Extent and Ice Production in the Ross Sea

    Science.gov (United States)

    Comiso, Josefino; Kwok, Ronald; Martin, Seelye; Gordon, Arnold L.

    2011-01-01

    Salt release during sea ice formation in the Ross Sea coastal regions is regarded as a primary forcing for the regional generation of Antarctic Bottom Water. Passive microwave data from November 1978 through 2008 are used to examine the detailed seasonal and interannual characteristics of the sea ice cover of the Ross Sea and the adjacent Bellingshausen and Amundsen seas. For this period the sea ice extent in the Ross Sea shows the greatest increase of all the Antarctic seas. Variability in the ice cover in these regions is linked to changes in the Southern Annular Mode and secondarily to the Antarctic Circumpolar Wave. Over the Ross Sea shelf, analysis of sea ice drift data from 1992 to 2008 yields a positive rate of increase in the net ice export of about 30,000 sq km/yr. For a characteristic ice thickness of 0.6 m, this yields a volume transport of about 20 cu km/yr, which is almost identical, within error bars, to our estimate of the trend in ice production. The increase in brine rejection in the Ross Shelf Polynya associated with the estimated increase with the ice production, however, is not consistent with the reported Ross Sea salinity decrease. The locally generated sea ice enhancement of Ross Sea salinity may be offset by an increase of relatively low salinity of the water advected into the region from the Amundsen Sea, a consequence of increased precipitation and regional glacial ice melt.

  15. Mapping the deep sea floor

    DEFF Research Database (Denmark)

    Nielsen, Kristian Hvidtfelt

    By the early 20th century, oceanographers intensified their efforts to map the deep sea. The great depth of the Philippine Trench was first observed by the German Planet Expedition in 1912. During World War II, the US naval vessel Cape Johnson used directional echo-sounding to obtain a depth of 10...... Trench in order to map its bathymetric features. The resulting maps are presented in this poster. Unlike many other contemporary developments in deep sea topography and cartography that were shaped by the Cold War, the Galathea maps of the Philippine Trench were intimately connected with the expedition......'s attempt to "wave the Danish flag". The expedition was the first scientific expedition to have on board a separate press section communicating its scientific results as well as Danish nationality to the wider public. In this poster, the Galathea maps of the Philippine Trench are placed within this context...

  16. Scaling the Baltic Sea environment

    DEFF Research Database (Denmark)

    Larsen, Henrik Gutzon

    2008-01-01

    The Baltic Sea environment has since the early 1970s passed through several phases of spatial objectification in which the ostensibly well-defined semi-enclosed sea has been framed and reframed as a geographical object for intergovernmental environmental politics. Based on a historical analysis......-scientific logic, but should rather be seen as temporal outcomes of scale framing processes, processes that are accentuated by contemporary conceptions of the environment (or nature) in terms of multi-scalar ecosystems. This has implications for how an environmental concern is perceived and politically addressed....... of this development, this article suggests that environmental politics critically depend on the delineation of relatively bounded spaces that identify and situate particular environmental concerns as spatial objects for politics. These spaces are not simply determined by ‘nature' or some environmental...

  17. Micromechanics of Sea Urchin spines.

    Directory of Open Access Journals (Sweden)

    Naomi Tsafnat

    Full Text Available The endoskeletal structure of the Sea Urchin, Centrostephanus rodgersii, has numerous long spines whose known functions include locomotion, sensing, and protection against predators. These spines have a remarkable internal microstructure and are made of single-crystal calcite. A finite-element model of the spine's unique porous structure, based on micro-computed tomography (microCT and incorporating anisotropic material properties, was developed to study its response to mechanical loading. Simulations show that high stress concentrations occur at certain points in the spine's architecture; brittle cracking would likely initiate in these regions. These analyses demonstrate that the organization of single-crystal calcite in the unique, intricate morphology of the sea urchin spine results in a strong, stiff and lightweight structure that enhances its strength despite the brittleness of its constituent material.

  18. Micromechanics of Sea Urchin spines.

    Science.gov (United States)

    Tsafnat, Naomi; Fitz Gerald, John D; Le, Hai N; Stachurski, Zbigniew H

    2012-01-01

    The endoskeletal structure of the Sea Urchin, Centrostephanus rodgersii, has numerous long spines whose known functions include locomotion, sensing, and protection against predators. These spines have a remarkable internal microstructure and are made of single-crystal calcite. A finite-element model of the spine's unique porous structure, based on micro-computed tomography (microCT) and incorporating anisotropic material properties, was developed to study its response to mechanical loading. Simulations show that high stress concentrations occur at certain points in the spine's architecture; brittle cracking would likely initiate in these regions. These analyses demonstrate that the organization of single-crystal calcite in the unique, intricate morphology of the sea urchin spine results in a strong, stiff and lightweight structure that enhances its strength despite the brittleness of its constituent material.

  19. Allergy to sea fishing baits.

    Science.gov (United States)

    Félix-Toledo, R; Pagán, J A; Hernández, J; Cardona, G; Postigo, I; Martínez, J

    2005-01-01

    We report a new case of rhinitis and asthma caused by sea fishing baits. The results showed exposure to Sipunculus nudus (Phylum Sipuncula; order Sipunculida: Sipunculidae) to be the main cause of the allergic symptoms. The intervention of IgE was demonstrated, with the presence of cross-reactions with allergenic extracts from other worm species used as baits, belonging to different orders of Annelida.

  20. Heavy metals in sea turtles

    Energy Technology Data Exchange (ETDEWEB)

    Witkowski, S.A. (Millersville State College, PA); Frazier, J.G.

    1982-07-01

    Bone and barnacle samples from sea turtles (Hepidochelys olivacea) in Ecuador were analyzed for manganese, iron, copper, zinc and lead. Analysis was performed by flame atomic absorption spectroscopy. Results show that zinc and iron levels in bone and barnacles were greater than copper, manganese and lead levels. The significance of the findings is difficult to interpret because so little is known about baseline levels and physiological effects of heavy metals in the animals. (JMT)

  1. Growing halophytes floating at sea

    Directory of Open Access Journals (Sweden)

    Ricardo Radulovich

    2017-11-01

    Full Text Available Freshwater shortages are increasingly limiting both irrigated and rainfed agriculture. To expand possibilities for controlled plant production without using land nor freshwater, we cultivated potted halophytes floating at sea that were provided with rain- and seawater. Plantlets of two mangroves (Avicennia germinans and Rhizophora mangle and plants of two herbaceous species, sea purslane (Sesuvium portulacastrum and salt couch grass (Sporobolus virginicus were grown in near-coastal tropical Pacific waters of Costa Rica for 733 days. There were a total of 504 rainless days, including two dry periods of ca. 150 d long each, evidencing prolonged and exclusive reliance on seawater. Pots with a sandy soil mixture and the transplanted plants were placed on low-cost wooden floating rafts with their lower end perforated and immersed for capillary rise of water. Free seawater entry and exit through the bottom from bobbing with waves, which also occasionally added water from the top, effectively controlled soil salinity build-up even during the rainless seasons. Continuous leaching made necessary frequent fertilizer addition. No water deficit symptoms were observed and midday canopy temperature during rainless periods was not significantly different between species or from air temperature. With all-year-round growth, height increase of mangrove plantlets ranged from 208.1 to 401.5 mm yr−1. Fresh biomass production of sea purslane and the grass was 10.9 and 3.0 kg m−2 yr−1 respectively. High yield, edibility and protein content of 10.2% dry weight established sea purslane as a potential crop. While further research is needed, the method evidenced to be a viable plant production option of potentially far-reaching applications.

  2. Sea sand for reactive barriers

    International Nuclear Information System (INIS)

    Garcia R, G.; Ordonez R, E.; Ordonez R, En.

    2002-01-01

    Some phosphates have the property to suck in radioactive metals in solution, what it is taken in advance to make reactive barriers which are placed in the nuclear waste repositories. In an effort for contributing to the study of this type of materials, it has been obtained the zirconium silicate (ZrSiO 4 ) and the alpha zirconium hydrogen phosphate (Zr(HPO 4 ) 2H 2 O) starting from sea sand in an easy and economic way. (Author)

  3. Chemical munitions dumped at sea

    Science.gov (United States)

    Edwards, Margo; Bełdowski, Jacek

    2016-06-01

    Modern chemical warfare is a byproduct of the industrial revolution, which created factories capable of rapidly producing artillery shells that could be filled with toxic chemicals such as chlorine, phosgene and mustard agent. The trench warfare of World War I inaugurated extensive deployments of modern chemical weapons in 1915. Concomitantly, the need arose to dispose of damaged, captured or excess chemical munitions and their constituents. Whereas today chemical warfare agents (CWA) are destroyed via chemical neutralization processes or high-temperature incineration in tandem with environmental monitoring, in the early to middle 20th century the options for CWA disposal were limited to open-air burning, burial and disposal at sea. The latter option was identified as the least likely of the three to impact mankind, and sea dumping of chemical munitions commenced. Eventually, the potential impacts of sea dumping human waste were recognized, and in 1972 an international treaty, the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter, was developed to protect the marine environment from pollution caused by the dumping of wastes and other matter into the ocean. By the time this treaty, referred to as the London Convention, was signed by a majority of nations, millions of tons of munitions were known to have been disposed throughout the world's oceans.

  4. Sea ice algae in the White and Barents seas: composition and origin

    OpenAIRE

    Ratkova, Tatjana N.; Wassmann, Paul

    2005-01-01

    To examine algae populations, three expeditions (in March 2001, April 2002 and February 2003) were conducted in the Guba Chupa (Chupa Estuary; north-western White Sea), and one cruise was carried out in the open part of the White Sea in April 2003 and in the northern part of the Barents Sea in July 2001. Sea ice algae and phytoplankton composition and abundance and the content of sediment traps under the land-fast ice in the White Sea and annual and multi-year pack ice in the Barents Sea were...

  5. Radioactivity in the Arctic Seas. Report for the International Arctic Seas Assessment Project (IASAP)

    International Nuclear Information System (INIS)

    1999-04-01

    This report provides comprehensive information on environmental conditions in the Arctic Seas as required for the study of possible radiological consequences from dumped high level radioactive wastes in the Kara Sea. The report describes the oceanography of the regions, with emphasis on the Kara and Barents Seas, including the East Novaya Zemlya Fjords. The ecological description concentrates on biological production, marine food-weds and fisheries in the Arctic Seas. The report presents data on radionuclide concentrations in the Kara and Barents Seas and uses these data to estimate the inventories of radionuclides currently in the marine environment of the Kara and Barents Seas

  6. Offshore Wind Atlas for Northern European Seas

    Science.gov (United States)

    Hasager, Charlotte Bay; Karagali, Ioanna; Astrup, Poul; Badger, Merete; Mouche, Alexis; Stoffelen, Ad

    2010-12-01

    Offshore winds are investigated in detail in the EU- Norsewind project - short for Northern Seas Wind Index Database - that aims to produce an offshore wind atlas for the Northern European Seas including the Baltic Sea, the North Sea and the Irish Sea. The results are preliminary as they are from mid-term in the project (2008-2012). The results include mean wind speeds from Envisat ASAR, QuikSCAT and SSM/I compared to masts. The spatial variability across the area is clearly identified with major coastal effects in the enclosed seas. The long-term trend analysis does not indicate any trend in the different wind speed bins investigated during 23 years. The next step is further comparison to ground-based lidar data and atmospheric model results.

  7. DNMI revolutionises search and rescue at sea

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The Norwegian Meteorological Institute (DNMI) is offering new mathematical models which speedily can determine the direction of small, drifting objects at sea. The new mathematical tool will greatly improve the sea rescue of people, small boats and objects, and represents a considerable saving of valuable time. According to The Norwegian Search and Rescue Service headquarters at Sola, Stavanger, the work at DNMI will give Norway the world's foremost system for estimating drifting movement, and it will have a positive effect on all rescue operations along the Norwegian coast and in the North Sea. Fully implemented the new system will cover all of the Norwegian Coast, the North Sea, the sea areas outside Jan Mayen and the Barents Sea.

  8. GHRSST Level 4 ODYSSEA Mediterranean Sea Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at Ifremer/CERSAT...

  9. Oceanographic cruise: Coral Sea, Arafura Sea, and Java Trench, April - May 1969 (NODC Accession 7100914)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This report contains oceanographic data which was obtained aboard HMAS DIAMANTINA during an oceanographic cruise in the Coral Sea, Arafura Sea, and Java Trench...

  10. The lowering of sea surface temperature in the east central Arabian sea associated with a cyclone

    Digital Repository Service at National Institute of Oceanography (India)

    Murty, V.S.N.; Rao, D.P.; Sastry, J.S.

    An analysis of thermal Structure in the East Central Arabian Sea associated with a moderate cyclone is presented. The heat storage and the heat budget components have been computed. Under the influence of the cyclone the Sea Surface Temperature (SST...

  11. GHRSST Level 4 EUR Mediterranean Sea Regional Foundation Sea Surface Temperature Analysis (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily by Ifremer/CERSAT (France) using optimal...

  12. First biological measurements of deep-sea corals from the Red Sea.

    KAUST Repository

    Roder, Cornelia

    2013-10-03

    It is usually assumed that metabolic constraints restrict deep-sea corals to cold-water habitats, with \\'deep-sea\\' and \\'cold-water\\' corals often used as synonymous. Here we report on the first measurements of biological characters of deep-sea corals from the central Red Sea, where they occur at temperatures exceeding 20°C in highly oligotrophic and oxygen-limited waters. Low respiration rates, low calcification rates, and minimized tissue cover indicate that a reduced metabolism is one of the key adaptations to prevailing environmental conditions. We investigated four sites and encountered six species of which at least two appear to be undescribed. One species is previously reported from the Red Sea but occurs in deep cold waters outside the Red Sea raising interesting questions about presumed environmental constraints for other deep-sea corals. Our findings suggest that the present understanding of deep-sea coral persistence and resilience needs to be revisited.

  13. Retrieval of chlorphyll from the sea-leaving radiance in the Arbaian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Sathe, P.V.; Jadhav, N.

    the noise introduced at the sea surface. During the validation experiment of the optical sensor MOS-B onboard Indian Remote Sensing Satellite IRS-P3, simultaneous measurements of chlorophyll concentration and sea leaving radiance have been made along...

  14. Speciation studies of cobalt in sea water

    International Nuclear Information System (INIS)

    Toteja, R.S.D.; Sudersanan, M.; Iyer, R.K.

    1995-01-01

    Recent results on the speciation of cobalt in simulated and actual sea water is reported using ion exchangers. The influence of magnesium ions in affecting the composition of ion exchangers and subsequent interpretation of the results is discussed. The results indicated that Co +2 may predominate in both the simulated and actual sea water and the presence of other constituents in sea water does not affect the nature of complex species present. (author). 2 refs., 3 tabs., 1 fig

  15. The International Arctic Seas Assessment Project

    International Nuclear Information System (INIS)

    Linsley, G.S.; Sjoeblom, K.L.

    1994-01-01

    The International Arctic Seas Assessment Project (IASAP) was initiated in 1993 to address widespread concern over the possible health and environmental impacts associated with the radioactive waste dumped into the shallow waters of the Arctic Seas. This article discusses the project with these general topics: A brief history of dumping activities; the international control system; perspectives on arctic Seas dumping; the IASAP aims and implementation; the IASAP work plan and progress. 2 figs

  16. Sea otter health: Challenging a pet hypothesis

    OpenAIRE

    Lafferty, Kevin D.

    2015-01-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of...

  17. Sea otter health: Challenging a pet hypothesis

    Directory of Open Access Journals (Sweden)

    Kevin D. Lafferty

    2015-12-01

    Full Text Available A recent series of studies on tagged sea otters (Enhydra lutris nereis challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission.

  18. Sea otter health: Challenging a pet hypothesis.

    Science.gov (United States)

    Lafferty, Kevin D

    2015-12-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission.

  19. Sea otter health: challenging a pet hypothesis

    Science.gov (United States)

    Lafferty, Kevin D.

    2015-01-01

    A recent series of studies on tagged sea otters (Enhydra lutris nereis) challenges the hypothesis that sea otters are sentinels of a dirty ocean, in particular, that pet cats are the main source of exposure to Toxoplasma gondii in central California. Counter to expectations, sea otters from unpopulated stretches of coastline are less healthy and more exposed to parasites than city-associated otters. Ironically, now it seems that spillover from wildlife, not pets, dominates spatial patterns of disease transmission.

  20. Multiscale Models of Melting Arctic Sea Ice

    Science.gov (United States)

    2014-09-30

    Sea ice reflectance or albedo , a key parameter in climate modeling, is primarily determined by melt pond and ice floe configurations. Ice - albedo ...determine their albedo - a key parameter in climate modeling. Here we explore the possibility of a conceptual sea ice climate model passing through a...bifurcation points. Ising model for melt ponds on Arctic sea ice Y. Ma, I. Sudakov, and K. M. Golden Abstract: The albedo of melting